I can't really argue with anything said here. The only thing that I can add is buy as nice a guitar as you can afford, and stay away from any off-brand cheapo stuff. If you can get into a decent used MIM Fat Strat for around that $300 price point, it should take you reasonably far sound-wise, and at worst you can always flip it for the same money you bought it for. BTW, you will discover that no single guitar will ever do everything you want it to...
Also, I'm assuming you're also in the market for an amp? If so, I'd strongly recommend one of the newer modeling amps, so at least you can approximate the range of tones you're looking for without spending another chunk of money on stompboxes. While it is true that they are definitely not perfect, at least you can get a better feel for what you might want. Unless you already know that you like a Class A tone with a bit of clipping, or a super clean Roland-type jazz sound, blah blah blah. Also, be sure that it has enough wattage to play over drums (20w+ tube, 50w+ solid state if you can manage). Oh! And make sure you can move it, by yourself.
