Cable vs DSL ***TOTALLY*** depends on your local providers. Having moved several times in the past four years, plus having visited my friends all across the USA, I have seen it all. I've seen awesome DSL, I have seen sucky DSL, I have seen awesome cable modems, I have seen sucky cable modems. Find out what your local DSL and cable modem providers offer and find out (via word of mouth) how close they really are to their claimed specs. Reliability might also be important to you as well.
Where I currently live we can get 2 Mbit SDSL (2 Mbit up, 2 Mbit down) from the local telco, we can also get from the cable company a modem that will do 3 Mbit down but only 512 kbit up. It's always a tradeoff, so do your research.
Yes, I have read about how DSL is "private" and cable is "shared", this might be technically true, but what's more important is how much bandwidth your ISP really has behind their routers... because really, it's all shared at the ISP level anyway.
Beware of overinflated specs. I have seen cases where "5 Mbit cable modem" does indeed mean 5 Mbit... to the ISP! But the real world internet benchmarks show downloads that are closer to just 1 Mbit. I have seen this with DSL as well.
Real world performance (speed and reliability) differs more due to company policy and company routers and upstream internet providers. The "last mile" technology (DSL and cable modems) usually have less to do with the overall experience.