Hey guys, sorry for the gratiutous self-link, but some may be interested in reading up on my setup for p2p over ADSL.
I think it's useful because I followed the router charts on Tom's Networking, and the one they claimed was 'fastest' was actually totally apalling in my opinion.

I ended up with the combination of a Dynalink RTA1320 modem and Linksys WRT54GL running DD-WRT.

The key thing was the ability to alter the NAT table behaviour of the WRT54GL, which really seemed to help bittorrent performance.

Happy to answer any questions.