It depends of what you want to do. If you're more of a PvP-er, just do some quest and go PvP and QQ about the unfair advantages other classes have.
If you're a PvE-er (like I was), don't bother. By the time you'll be optimised for the latest raid tier, the new expansion'll have hit the shelves (or it will be close to).
WoW is a game that needs to be played on length, casual and hardcore alike. If you don't invest enough time (and money

), it's useless to play. Or maybe, if you just wxant to discover all the new quests, by all means, resubscribe for a month or two, start a new char and explore.
