Well if you ever plan on moving your computer DSL is better because any phone jack in your house/office can be used. With cable, you have to have a new cable outlet installed.
Some Cable modems are only one way and use a dial-up line for the upload bandwidth. Mostly the older ones, I think they have had bi-directional cable modems for a while now. Download bandwidth is always faster than upload bandwidth on Cable and DSL connections.
DSL bandwidth depends on how close you are to the switching office that houses the DSLAM, the further away you are from the DSLAM the slower your bandwidth will be. Could mean the difference between a 384Kbs and 128Kbs Download Bandwidth for residential DSL. Business DSL costs more, but they can crank it as high as 1Mbs for a higher price. If you are really far away from the DSLAM, you might not even be able to get DSL. If your DSL bandwidth is very slow, you might do better to get Cable.
I used to work a Help Desk for a Baby Bell DSL hotline and we took three weeks to study how DSL works.
Some DSL companies block server protocols for Dynamic IPs, like the Baby Bell company I subscribe from. So TWGS only works at the login screen and after a player gets into a game, they shut down the protocol and cut the connection. I guess if you pay for a static IP they don't block server protocols? Speakeasy doesn't do that, but they charge a bit more.
http://www.speakeasy.net/ I might switch there when my DSL contract runs out.