Hey and welcome to the forums! I'm new also (there's alot of us I see) and yes, one day you'll be 5-boxing it =P I started with 2 in September and moved to 5 a few days after I discovered this site. But...starting with two...maybe two mages? or warlocks? /agree with Oz

Also, maybe two shaman. They are pretty popular around here. Since you just started, it doesn't hurt to play around with different combos. Figure out what you enjoy playing and go for it. Since you're only running two you don't need a balanced crew just yet. Whatever you choose, have fun and good luck leveling!