dsl or cable modem

It depends on the speed of each. My DSL was about 300-350kbps
I now have cable at @1000-1250kbps.
I switched because I have seen the cable in my area as high as 2100kbps on another persons connection.
I know some areas don't have as good a cableconnection. Cable is shared among all users on a segment whereas DSL is an exclusive connection between you and the switching station. I have also seen 1.5mbps dsl offerings so you have to check prices and it helps to know someone nearby with cable to verify actual speed.

It somewhat depends on what you use your connection for.

If you upload a lot of data, then you want SDSL.

If you mainly download, cable should work okay, but does suffer from a shared connection that can slowdown at peak usage times.

ActualDSL speed drops the farther you are from the switch that serves you, and is very dependant on the quality of the wireing between you and the switch.
NOTE: the distance is based on the route the wires take between you and the switch. This can be considerably longer than the driving distance.

Another factor to consider, is that if you plan to move in the near term, cable is more transportable than DSL.

It is also possible that your expectations are too high. Before making a switch, verify what your actual connection speed is. There are numerous utilities that you can download to verify your cable connection speed.

Check out the web sites dslreports and cable reports to see how your cable provider rates, and to check on the quality of DSL servive available to you.