So I'm sure similar questions have been asked many times before, but...
The only mic I currently own is a Behringer B-2 Pro.
I'm in the process of buying an 8-channel preamp and interface, and some multicore to be able to record more than just a stereo mix (I've been doing mainly field recordings so far).
I'm mainly going to be recording vocals, acoustic guitars, and probably eventually a bit of bass guitar / double-bass, and a drum kit.
I was thinking of getting a matched pair of AKG C451s, and another B-2 Pro to make it up to a pair. Then I could record the vocals with the B-2 Pro, and the guitars with the two C451s - maybe a B-2 Pro if I really want flexibility in mixing

.
Is this a good idea? Am I totally crazy? Should I get a cheaper/different pair of small-diaphragm condensers (Samson C02? SM81? etc), and get a pair of SM57s? Should I forget about small-diaphragm condensers entirely, just use my B-2 Pros, and get some nice dynamic mics for the drum kit and to close-mike the guitar as well?
Sorry for all the newbie questions. I've just been used to playing around in studios with the kit they've got, never having to buy my own :P.
(Oh, and my budget is probably no more than $700 or so for the mics).