@ Ztalker: I've been playing on the beta servers with a ping of around 282ms so you'll be just fine.
But yeah, as Mav said, for the PvE (Player vs Environment) server that the LF guilds will be one, these levels of ping are fine. PvP (Player vs Player) servers on the other hand, you'd get your butt handed to you since you're facing off against other real life people with pings that are most likely under 50ms so they'd end up having around 200ms head start on you for every attack and move. Doesn't sound like much but it can be brutal.
Luckily, no one has to play PvP if they don't want to so it's no problem.