Maybe the info in this thread will help you: Which server for alliance PvE. I would recommend one of the two bigger PVE realms. PVP servers tend to be way more unstable. Also, in my personal opinion, PVE servers have a much nicer community (on average, of course). Bonus: No “world PVP” aka griefing. There is enough people to play with, don’t worry.
Also, if you want a boost, you could also go for the 70 boost. It will propably be more ecpensive, though, and is not yet available.