New to GW2. Any server+prof recommendations?

Herro. I'm just looking to see if you guys have any recommendations for me in terms of server and profession based on my gaming/interest background. I'm pretty much a noob still in terms of GW2. Never played the first, lost interest in GW2 after getting 14 lvls in on release day due to Skyrim and TERA.

Only other MMORPGs i've played are FFXI(8-9 yrs), WoW(2 yrs or so, stopped when BC came out since I was close to Grand Marshall but, didn't make it in time.), handful of K-f2ps, SWOTR and TERA.

The things I'm looking forward to in GW2 is grouping, getting into an active guild, and PvPing.

The classes at the moment I'm trying to decide between are Engineer, Thief, and Mesmer due to them not being as common but, unsure of just which to choose.

Anyways if someone can point me in the right direction, it would be much appreciated. I plan on starting fresh in a few hours or so. Or whenever I get enough replies. In the meantime I'll just play LoL and some guitar to pass the time.