Blizzard sorc is probably still undisputed (best boss killer)
Meteorb is always great (fewer immunes)
Hammerdin always works as a starter, but lags behind a sorc unless you get insanely lucky finding hrs. Being able to farm keys + kill ubers is a big plus
Java is also decent, slaughters cows about as fast as McDonald's
If you want a less Cookie-Cutter char, here's a few fun ones to try:
War cry barb! You farm Travical and get ALL the runes! Warcry skillers go for about a pul each early on in the ladder and you just need something like an obedience for your merc and he'll wreck
PSN Necro! You get about 250 mf and oneshot everything in the pits