Latency

Your latency is not a set thing that you get from your ISP. It's not like bandwidth where you have a "pipe" of a certain width that is always roughly the same size. Latency, rather, is the time it takes for your computer to communicate with another, and this varies depending on what computer you're trying to talk to. If you're trying to talk to a computer in Yemen, your latency will be large. If you're trying to talk to a computer on your local network, it will be negligible (to the point you'd have a hard time measuring it with standard software).

Further complicating the matter is that latency isn't just based on distance. It also depends on how many intermediate computers (routers) your traffic has to go through on the way, and how congested those computers are. Think of it like a road. Distance from point A to point B affects your arrival time, but so do stoplights (routers), number of other cars on the road, etc.

What this all means is that you can't rely on your latency to one server to predict your latency to another. Even if they're located in the same town. There's no telling how your traffic will be routed (there are an enormous number of possible routes), or what the network conditions will be like on the way.

Upload Speed

For online games, much more is downloaded than is uploaded, it's just that most internet connections have very limited upload speeds. However, for MOST games, the required upload bandwidth is very small. It's difficult to find hard data on this, but anecdotal evidence suggests that even 64kbit is perfectly adequate. All you're really transferring is your character's status. Position, time when you fire a bullet, etc. Nothing too intensive. This is around .07 of a megabit.

The big exception: hosting. If you're playing a game without dedicated servers, and you want to be the host, you'll need the above number for EACH player. In which case, yeah, you could definitely run into issues with upload speeds in the 0.25 - 0.5mbit range.