I have AT&T cable in the Chicago Metro area.
I haven't tried HTTP, but SSH (in and out) as well as FTP (in and out) both work jus' fine.
Don't forget to open the holes in your firewall (if you have one). Forward 20 & 21 for FTP, and 22 for SSH.
Deciding to toss DSL is gonna depend on your traffic habits. Cable tend to have faster downlinks, DSL tends to have faster uplinks.
Good Luck
Scott