There are sooo many ways to split $600 on mics.
The 603's or 012's are going to do at least a reasonable job on overheads and acoustic (and percussion, piano or whatever). For the money you can't really beat them, although you could sub in a pair of Studio Projects B1's for a similar price.
The sm57 for snare is the most widely used choice. Of course, it may not ring your bell, but it's a great starting point, and also useful on vocals, and guitar amps. Daniel Lanois uses them for acoustic (which I can't fathom - mine sounded terrible when I did that).
I would also want a dedicated kick mic (which may have other uses), and similarly at least one dedicated vocal mic. It's your choice whether you spend up big on a kick mic and get a cheaper vocal mic, knowing that the kick mic will possibly serve well on vocals (as in the 421) or spend up big on vocal mic or mics, and end up with a cheaper (and possibly less useful for other things) kick mic.
The 421 is a great mic, and you will never need to upgrade (though you may want to add other colours). It's not just a kick mic. It can be great on bass amps, guitar amps, some vocals, brass, sax, low toms,...
On the other hand, something like a 4040 is likely to be good on voices, acoustic, percussion, guitar amps.
You pays your money and takes your choices. I suggest trying out as many different decent vocal mics as possible with the voice/voices you'll be recording. You may surprise yourself with which sounds best.
Steve