Well I have ISDN and can crank it to 128K when I need to. I have found this is more than enough. 64K is usually fine.
In fact most servers I come across in my limited exp. are just guys running the game on their own PC and not dedicated servers. Once they get more than 3 or 4 players, THEIR system can't cope, not the bandwidth.
I've had <100 ping and still get lag. That's THEIR PC, not my connection. Try a dedicated server and you'll see what I mean. I played for a few mins last night on one of the gamedomain test ones. Ping 150. 32 Players all going for it, no lag at all.
Later, 73 Ping. 5 Players, different server. Tons of lag.
I could be wrong, but that's my conclusion.
Steel