I race with this: (my first bike)
It's a Schwinn from Bikes Direct. It came with a triple compact which I've replaced with a double compact (after my first race season), bought a rear wheel with power tap and I just ordered a lighter wheel set that were on sale (HED C2). I've been holding out on the wheel purchase let alone a new bike purchase just because I don't think it'll really be a huge difference. I bought the wheels mainly for my own "oooh! new bike stuff...time to ride more!" Told myself I'd get a new bike when I get Cat 3.
Buy what you can afford and ride/race lots then figure out which direction you want to move from there.