Glass cannon pokemon are great, unless you hit Trick Room teams.
Aerodactyl is really good, with great moves, 130 base speed, including STAB AoE Rock Slide if you like double/triple battles.
Starmie is also awesome, I go with the 'Death Star' moveset (BoltBeam, Psychic, Surf/Scald IIRC).
Jolteon with a good HP can also do serious damage.
I also like all four of the muskedeers, but it's REALLY annoying that Keldeo is unfairly banned, given that he's basically a special version of Terrakion, and he doesn't seem to have a great movepool, yet Garchomp is allowed (Cynthia is overpowered for this reason). Terrakion gets both Rock Polish, Swords Dance, and possibly better coverage than Keldeo. The offensive ones can do good AoE damage without boosts, and the defensive ones can get nasty with one Swords Dance. Helping Hand on all of them also allows them to fill a support role if you're using more than one in a double or triple battle. Getting 6-0 on Cynthia's Triple Battle team in the PWT using the 3 original muskedeers was AWESOME. 2x Helping Hand + Terrakion with Rock Slide = PAIN.
As for Battle Subway in White, not only did I use Cobalion (only muskedeer I recruited in that game), but I also used Volcarona (borderline overpowered, and totally awesome - Focus Sash + Quiver Dance = GG unprepared teams without priority moves) and stuff like Jolteon/Starmie for a >50 streak.