if it's skill just stick to last years games with a few older demos thrown in such as cooller ztn games, zero4 t4 games and random people for dm6 but no more than 2 years old really otherwise pointless apart from entertainment ;p
I've got one with cooller + unkind + ztn but they've played that many times, so go figure whether it's the right one... probably still good regardless :)
edit : scratch that. I thought wrong, I don't have any "cooller/unkind-on-ztn"s. I'll find something...
Fatal1ty vs zero4, Quakecon 2002 (dm6)
Very old game, but still relevant for anyone wanting to learn Q3 - fatal1ty does all the basics very well, and not much else.