the linksys wrt54g , gl, g++? is a mad old, still produced, and still selling a/b/g router.
It's pretty easy to set up and mess with (though you have a mac so i dunno how you'll feel about it) (the new version ships with some sort of auto-magical cd that might or might not work)
A cool thing is that it has a bunch of different 3rd party "firmwares" aka different embedded linux distros with web interfaces that are easy to use and work well. I've had one running hyperWRT (i dont know if it's maintained anymore) and set to push a few extra milliwatts through the antennae. (150% of stock)
The thing's been running for like 6 years now so it has a thumbs up from me
EDIT: ohi az