5
The answer depends on which DSL service provider the original questioner is asking about. They vary widely, especially the upstream bandwidth for residential services which is, as you say, the important issue for running a server. And there are, too, the questions of terms of service and acceptable use policies which also vary widely.
You're not going to get much better downstream bandwidth than 6 mbps (that's megaBITs/second BTW) from any DSL service provider, even with a commercial service. The more important question of upstream bandwidth can only be answered on a case-by-case basis. It requires more information about the telco operation that is involved.
Individual distance from the CO is also an important determinant of whether you get the full rating of any DSL service in either direction. And that means phone line distance, not line of sight or driving distance, which only your own telco knows for sure.
Bottom line: There are too many "ifs" involved to be able to provide one right anwser for everyone and a good answer for any one individual needs more detailed input.