Old player returning, few questions

I played originally on Eldar from game release for a couple of years, then quit just before Mines of Moria was released. I returned briefly in 2011 but it was short lived.

So what's new?

I've downloaded the game other than using my original disc, and set up a VIP sub (may aswell if I want to give it another go properly!).

What expansions will I need to get and at what levels? Can I get them as quest packs?

Also, what's the best tank? I just want to hit stuff and not worry too much about intricate builds and tactics while I get a feel for the game again, then maybe i'll try burg again once i've acclimatised :)

I've been giving Eldar another go the last few days as that feel like 'home' but it's so so quiet, where is everyone? Started a new toon on Mendrolin (if that's the name) last night and it was much busier - what I really want is a server that's not over run but busy enough for lots of social and FS opportunities, mostly UK players.

Anything else I should know? Thanks!