Mics??

I like my 57 and 58. For 600 you can get a mic and a pre.

I picked up a few MXL 603S pencil condensers recently to use for PA, but I have been surprised at how good they sound on recording.  You can pretty easily find a pair of these with nice case and great shock mounts for $150.  That's a real price performer.  I haven't tried them on vocals.  You'd probably want something higher end than that, but they work well on wind instruments.  They are way better than Samson and Behringer mics that look similar, and really not much more money.
 
I like the Rode NT4s a lot.  That's a stereo mic that is good for covering small choirs or other small ensembles where you really don't want to mic every voice independently.

Vokalzz,
 
I hear ya man, when I started in recording as a intern for a small LA studio, it was a bit of a mystery
for me as well but I learned some things that have really helpful along the way.
First, it might be easier to think of Mics as simply tools for a specific purpose and the Mic Pre's as
one of two kinds:

1. one that alter the sound or add color to the mic or,
2. ones that faithfully represent the Mic.

They both have their place and many of the pre amps that come in decent quality computer interfaces are not that much different than in stand alone pre amps. ( MOTU, RME, ECHO, ect )

So the lesson here is start with the right tool ( Mic ) and get better pre amps as you can afford them.  Mics like an SM57 or 58 ( and Beta )  are dynamic mics so while they are great for some jobs ( 57 on drums and guitar cabs is the studio standard ) they dont produce the detail that a higher end condenser mic will on say vocals or acoustic instruments and cymbals. I dont want to over simplify here cause there are always exceptions to the rules but here is a quick breakdown of what Mic's we use daily in a metal session:

Vocals: SM58 ( yep that's right ) or more often SM7B ( most of the modern rock/Metal stuff is cut with this Mic ). Both are dynamic and can take a lot of level and crazy range without breaking up. Sometimes on softer sections we will switch to a AT 4050 or a KSM44 for more detail and clarity.

Acoustic guit: 2x SM81 in a stereo pair or for mono tracks, just one angled at the 12th fret in towards the sound hole with the High Pass on. For brighter tracks sometime the AKG C451 or the C1000s for a cheaper alternative that dosn't suck.

Guitar Cabs: SM57, the old standard and probably the best desert Island Mic on earth. Sometimes the Sennheiser 906 for the additional pad options.

Drums: Kick, beta 52 or the Audix D6 period. Toms, Audix D2 on the Racks and MD 421 on the floors or the Beta 52 as well. Snare, SM57 top and bottom, sometimes the Shure SM56 on the top for more snap. Overheads, 2x SM81 or AKG C451s.

If I had to do a Rock/Metal session with only 2 mics and had under 500 hundred to spend, I would  probably choose:

1. SM57 ( 95.00 anywhere )  Can Mic almost any cab ( bass or guitar ) and can be used for vocals as well as a lot of percussion and other instruments.

2. Studio Projects C1 ( 249.00 and sounds like a pre EQ'ed U87 ). Best condenser for under 400 bucks on the
 planet...with the possible exception of the ADK Thor but that IS 400. bucks. The C1 is Killer on vocals, acoustic guitar, acoustic anything with the pad engaged and takes a crap load of input before it breaks up. A lot of the MXL, AKG Preception Series,  and Marshall stuff out there was patterned after this Mic. The company was bought out by PMI and the Mic is still made and labeled the C1.

Unless the Mic pre's in your audio interface really suck ( Line 6 UX series, ect ) you wont be improving your overall sound enough to warrant the expense. With that price range, you wont be able to afford the Mic Pre's that would really make an audible difference ( Avalon, Universal Audio, Neve, Chandler, Chameleon Labs, ect ) so spend your money on tools that will, better Mics.

YMMV, hope this helps