What class should I roll? (PvE)

I really want to do dungeons/raids and endgame progression in general. So for raids and such;

1. How good are frost mages?
2. How are holy paladins with questing and survivability?

Answers/class suggestions are much appreciated :)

For raids you are interested how holy paladins are with questing..?

Like in vanilla, mages are the middle ground for PvE DPS. They're not the best, but they're not bad either. They bring portals, food, can tank some bosses, and are decent in PvP.

Don't quest as Holy unless you're genuinely masochistic.

Resto shaman. They're very strong healers overall with their chain heals. On top of that, they are pretty self sustaining and stackable with mana tide totem. They're very flexible in terms of raid composition due to totems. Aaand they are pretty much the only healer which brings an insane DPS increase to the raid in the form of bloodlust.

If you have half a brain you can do really well as a resto shaman and because they are so desirebable you will not really have to compete for a spot. The fact that you're a resto shaman goes a long looooong way.

Generally speaking, each class has a viable leveling spec. Some classes have a "this was a bad choice" leveling spec (holy paladins being one such).

Mages in general are only in moderate demand (only one is truly required in a raid for Int, Biscuits, & portals; extra mages just depend on how well that player plays the class, as other dps can attain higher numbers). You can viably be a frost mage if you'd like (it's certainly a good leveling spec) for raids, but it is not the premier spec and is not highly desired as a fire (best for low gear and for aoe) or arcane (higher dps, but highly dependent on mana support from raid).

As a gross generalization (highly subjective, but the gist of things), Resto Shamans are probably the most in-demand healer for raids, any healer for 5-mans, Prot Warriors are the most in-demand tank for raids, Prot pallies the most in demand healer for 5-mans, mages might be the highest in demand for 5-man dps, and Warlocks/Hunters the most in-demand for raids.

Those are, again, just the gist. Most guilds recognize that many specs are viable when manned by a competent player. Nearly all raids will have a spot set aside for a shadow priest, enahancement shaman, an extra paladin (be it holy or ret), and other such classes that provide utility bonus to the group via buffs or sustainment.

I suppose, in the end, I would say that if you don't know where or what you want to do, and you don't have a support group awaiting you (friends in a guild), then roll shaman or druid. Good versatility, and you'll find a spot somewhere.

Frost mages are really good for pvp, pve not so much because frost mages are built around ice nova giving higher crit chance and using frost bolt and ice lance when they're frost nova'd to get lots of burst which means more aggro. Holy pallies have really good survivability but they aren't good for questing. But they're also really easy to heal on, just spam flash of light and throw in holy light every once in awhile.