I watched the first three seasons that way, buying the DVD set and just burning through it, several episodes per night. The first season I watched as it came out was Four, and just as with you and Three, Four ended up being my least favourite season. I couldn't stand it, and was endlessly bored. I tried the same with Five and Six, and with Six I actually gave up watching it halfway through and never finished. But for Seven and Eight I returned once they were finished and watched them in big bunches all at once again, and enjoyed them a lot more.
For this new season, I'm wondering if I should wait until they're all out, or if the shortened season and reduction of filler will make it easier to watch once per week for ten more weeks. I actually already watched the first two, being curious. It was still 24, which means it was still a bit ridiculous, but it was fun and Keifer Sutherland is still iconic as Jack Bauer. The plot definitely seemed more focused. So maybe I'll try watching it the normal way.
Chapterfish — Nate's Writing Blog
http://chapterfish.wordpress.com