Depends on what you're looking for I guess. I would recommend giving WoW a shot if you've never played before, It's like 2 or 3 months into a new expansion and is in a really good place right now to jump in. If you're looking for Raids and PvE stuff, this is the way to go. PvP is great as well, but it has a steep learning curve. Alternatively I would also check out ESO (Elder Scrolls Online), Especially if you want more of a story/exploration focused style MMO. Dungeons and raids are a little lackluster (Less Complex, significantly easier outside of 'Veteran' raids and DLC dungeons.) compared to wow, and I never touched PvP but it exists. Can't really go wrong either way, I'd say go with whichever one looks like more your style cause they play pretty differently.