What's your budget? 10-million, 10-thousand, 10-bucks?
Not to turn you off, but if you are thinking about making a traditional next-gen MMO type game, your going to need a multi-million dollar budget. The first America's Army game had a reported budget of "about 7-million".
If you are really creative, you can make something super-cool for 10 bucks (which would buy you a case of Jolt cola
). But it isn't going to be Warcraft or Counter-Strike.