Which of the three is most effective when it comes to daytrading? My style is one of speed, looking for quick access to the markets. It seems to me that cable would be most advantageous since it can send as much as 10Mbps of data downstream. The downside is however that it becomes slower when other users are on your same line. But can cable become slower than the maximum 384kbps that DSL offers? Any help from experience would be greatly appreciated.
the maximum 384kbps that DSL offers...
Might be the area I live in (although it's a fairly small city) but my DSL is currently rated at 768kb, and the provider offers 1.5mb DSL for about $20 more per month. Another avenue to consider, if speed is of the utmost importance, is a fractional T1 line. It will be more expensive than cable or DSL, and is not offered in all areas, but it is fast.
BTW, this would have been an excellent thread for the Hardware forum.