Try to find a local ISP (Score 1)

In my search for cheap personal colocation, I found that the best place to start is with small local ISP's. They're often willing to offer you flat rate (i.e. not usage-based) colocation for any server you want (1U, 10U, server tower, whatever). The prices I found across the lake here in Wisconsin varied from about $150/month to $300/month, all for more-or-less the same thing: they'll put your server in their offices and hook it up to their backbone, letting you use however much bandwidth you want. Obviously these places don't have oodles of bandwidth (the place I went with had 3mb/sec total), but unless you're doing lots of filehosting or something that's probably not such a problem. Also, since these little Mom and Pop ISP's don't usually do much more than residential dial-up and whatnot their usage is primarily downstream, giving you fairly full usage of their upstream bandwidth.

If you're willing to travel to Chicago, DLS.net does 10mb/sec unmetered colocation for $300/month. I didn't go with them and thus have no personal experience, but they seemed pretty good, and they're much better-connected than most (100mb/sec to Genuity, 45mb/sec to UUNet).

BTW, I'm using my colocated box for pretty much what you're using it for -- a couple Quake III servers, e-mail, and whatnot -- and it works out pretty well. I pay $250/month, though, which is more than you seem to be looking for.