About a month ago, I finally decided to replace my 5 y.o. computer. My budget was roughly $1000 and my goal was to basically get the best price/performance within that budget. I'm going to list what I ended up getting and why. Hopefully this will help someone going for a new desktop build. Any comments/feedback would be greatly appreciated...

Motherboard: Asus Rampage III Formula
I bought a used one from an enthusiast and it's in good condition. I went with this board because it seems like a great all-around board. Very overclocking-friendly, has Intel ethernet, and a feature that prioritizes gaming traffic over your network (obviously useful for gaming). I only bought this because I got a hefty discount off MSRP (ended up paying about $200). My alternative would probably be the Asus P6X58D-E (another great overclocking board or EVGA E768.. both are around the price I ended up paying.
R3F: http://www.newegg.com/Product/Product.aspx?Item=N82E16813131666
P6X58D-E: http://www.newegg.com/Product/Product.aspx?Item=N82E16813131641
E768: http://www.newegg.com/Product/Product.aspx?Item=N82E16813188065

Processor: Core i7 950
Well, when I compared prices with performance this was easily the best price/performance chip at the moment. I purchased it for $200 new. Sandy Bridge, the next generation of intel chips, is coming in about one month, but the initial release is more of a successor to the current i5 chips than the i7 ones. Sandy Bridge i7's (1355socket anyway) are probably still about a year away at least...
http://www.newegg.com/Product/Product.aspx?Item=N82E16819115211

Graphics: MSI GTX470 Twin Frozr II
This is supposed to be the coolest and quietest of the GTX470's and thus very overclockable. At MSRP, it's rather overpriced, but I picked it up for $225 on sale. Now that the GTX570 has been released, the prices should fall further. As much as I like the 570, at $350, it's out of my $1000 system budget.
http://www.newegg.com/Product/Product.aspx?Item=N82E16814127513

Memory: 6GB Super Talent Chrome PC-16000 ( 8-8-8-24)
I originally had my heart set on 6GB of Mushkin's new Redline Ridgebacks (which would fit the mobo's color theme perfectly ), but these ST sticks are better performing and I got a great deal, again from an enthusiast ($125 for 6GB... I'm in). This RAM uses Elpida hyper integrated circuits (ICs), which have had a reputation for failing. However, the newest revision of hypers seems to work fine at stock voltages. I plan to underclock these and run at tight timings instead. Plus, they come with a lifetime warranty so you're relatively safe. My alternative would definitely be the Redline Ridgebacks ($170). They're new, though, so you may see some price droppage. $170 for this might be overkill to be completely honest, though.
Super Talent: http://www.newegg.com/Product/Product.aspx?Item=N82E16820609488
Mushkin: http://www.newegg.com/Product/Product.aspx?Item=N82E16820226175

Power Supply: Corsair AX750
This is somewhat subjective and you may have different criteria for a PSU. I wanted one that was as efficient as possible and quiet as possible (presumably also very cool temps). This is definitely the PSU for that. Reviews say it makes no noise up to about 20% load and is pretty quiet even at heavier loads. It's fully modular, so better airflow in your case since you can use only the cables you need. And... 750W are more than enough for this build. I could add another GTX470 and still be under capacity. Who knows what the future really holds, but the GTX570 runs cooler and quieter than the 470, so perhaps we may even see a trend towards less power-hungry systems. So 750 Watts should be fairly future-proof, which is great since this has a 7-year warranty. Can re-use in a future build most likely. And oh, bought for $115 new.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139016

Hard drives: After Roland00's strong recommendations and doing my own reading on this, I decided to go with a solid-state drive (SSD) for my system files and a separate hard disk drive (HDD) for storing larger files. I'm fairly impatient myself and SSDs speed up boot times and file access times quite noticeably so to me it was worth it. I ended up going slightly over budget because of it, though.

System drive: OCZ Vertex 2 90GB SSD
I have to agree with the experts on this one... the SSDs using Sandforce controllers blow away most of the other SSDs out there in regards to performance. There may be some lingering reliability issues as these are newer, but they seem to have good value and the relative rate of failures are still pretty low. They connect via SATA II ports, like most regular hard drives. Of the various manufacturers selling Sandforce SSDs, OCZ is reputed to have the best firmware support, but this probably isn't a huge deal. Just by the cheapest one, or go with a brand you like. As for size, 60 GB should be plenty if you manage it well. I bought the 90GB because it was on sale for what the 60GB were selling at... around $115.
http://www.newegg.com/Product/Product.aspx?Item=N82E16820227611

Storage drive: Western Digital 1TB Caviar Black
I'm actually running this as my system drive at the moment and it was a huge upgrade from my old drive (which it replaced after it failed). It's pretty fast in it's own right, but nothing close to what the SSD can do. I bought this drive without doing as much research as I should have, but I did need a replacement quickly. I have nothing against this drive's performance, it's great. However, the Samsung 1TB Spinpoint F3 is cheaper and basically just as fast (or faster in some respects). I would save my money and go with the Samsung. If they were the same price, I'd probably go with the WD because of slightly better performance in gaming, but both are good. The Samsung is ~$55, the WD is ~$80.
WD: http://www.newegg.com/Product/Product.aspx?Item=N82E16822136533
Samsung: http://www.newegg.com/Product/Product.aspx?Item=N82E16822152185

Case: ???
I actually haven't bought a new case yet. I'm going for a mid-tower, mostly because a full tower is just too big for my workspace (although much better than a mid tower in many other ways). I'm interested in an aluminum case because they tend to be relatively light-weight compared to the usual steel/plastic combos. They tend to be a bit more expensive as well, but I'm OK with that because of the lower weight and they also look nicer in my opinion. I'm considering Lian Li PC-7FN or PC-60FN. If you have other recommendations, I would be glad to hear them.

Closing thoughts: Well, this took up a significant amount of time to actually research everything (and track down the right deals), but I found it to be pretty fun and I've discovered some neat ways to stay somewhat up-to date with the big tech changes going forward. Hopefully some of this info will help someone just now starting down the same path.

Now, I realize I still need to get a good cooling system. I want to just take the easy way out (and cheap way out) and get a Cooler Master Hyper 212 (~$10-15), but we'll see. I would love to read any recommendations you have. I know Noctua is probably the best choice for heavy duty air cooling. I'm not against doing liquid cooling, but it will require more effort on my part and likely be much more expensive. From what I gather, a low-end (relatively affordable) liquid cooling system like a Corsair H50 is not better than the Noctua anyway.

Sandy Bridge: I hear some rumors about this and they are generally positive. If you are planning an i5 build, I would probably wait until after Sandy Bridge 1155 is released (in about a month). However, pricing for SB 1155 seems closer to the current i7 1366 levels than i5 1156 ones, so it may not help too much in that regard unless intel makes some last minute changes.

Graphics cards: If you're in the market for a high-end card, at the very least you should wait until AMD/ATI release their 6900 series (next week or so I think). If it's a hit, that will probably cause NVIDIA to lower prices on their 500 series. And the 400 series should start to fall in price soon as well.

The bill: $200+$200+$225+$125+$115+$115+$80 = $1060 (w/o case or cooling); this does include the $115 SSD, so without that, it's definitely in my original ballpark even with a case.

Alright, I think I've said more than enough at this point. If you're so inclined, please comment or give feedback on anything you liked/disliked or would change/recommend.