Talk to people in your area 1st and foremost. Service interruptions vary from region to region.
I'd give the edge to cable for online gaming in my area. When playng CS my ping is usually ~80, but at my buddies with cable, it's about 50.
I can live with it though because most of the time his cable flakes out...
Some cable ISPs will soon have a cheaper rate capped service. In Ontario, it is called hispeed lite and is 128k u/l d/l and it is only $24.95 month.
Cable and aDSL in Ontario is about $35 to $40 month which is very cheap.
