I'm currently using my Samurott, Ampharos and Genesect. Undecided as to what else i'm going to train, as I normally plow through the games with 2 or 3 Poke's.
Samurott, Ampharos, Genesect, Swoobat, sawsbuck and sanslash. I replaced Sawsbuck with cobalion and replaced sanslash with Virizion for the elite four.