Which guitar cab mic should I get?

Maybe see if you can rent a few choice mics from a rental company/studio for a big re-amping session and see what mics you're leaning towards? With something like this it's hard to say. I haven't liked my SM7 on guitars at all but guys are getting good results, I've quite liked my D2 as a blend with a 57 but lots of guys say they hate it.

Never thought about that. Has to be way cheaper than just buying and selling if I don't like. Good idea man!

Thanks dudes, got about 5 mics I've never used or heard of I need to look into now.
 
I really dig an MD421 track with a 57 on my guitar cabs. Try dialing less gain and high end on your amp to get rid of fizz, when double tracking. My tone knob is around 10-12 o'clock on most of my amps with a TS. Also, move that fucker away from center of the cone in small increments and you'll get out of the fizz zone. Stick with that 57, it's not the cause of the bad tone.