Orb/Fireball Sorc

Go Blizzard, max most synergies (expect ice bolt), maxing cold mastery can be a very good idea if you lack +skills. Putting a few points in Static Field is a good choice aswell.

After that, you should hit Meph, Ancient Tunnels and Pindle. AT lacks natural cold immunes, Meph has 75 cold resistance which can be reduced to -100 with slvl 27 Cold Mastery which is one of the reasons to invest heavily or even max CM. Pindle and his goonies can be halted with Glacial Spike, and is an ideal target unless you can run AT with high efficiency.

You can also run Council(skip Toorc), Lower Kurast, Chaos Sanctuary (skip De Seis and Diablo) and some of the other alvl 85 areas, such as Crypt on Burial Grounds.

All in all, Blizzard sorc is the second best MF-char in the game; only bested by Pit-zerkers, who require some very heavy gear. It is also an ideal character to start the game with, since you have teleport to begin with and have an extremely damaging aoe spell.

/r/diablo2 Thread