Everything....nothing....it all depends on the project.

The ONLY thing I have not tried an SM57 or an SM7 on is OH mics from drums...but great recordings (IE Emmylou Harris' "Wrecking Ball" had 57s for OHs...and as always her records are superb)

In the past year, I've used 57s for (partial list): lead male or female vox, backup vox, guitar amps, upright bass, snare and kick drums, recording dogs barking, ambient sounds like trees rustling in the wind, voiceovers, micing Rhodes pianos from JBL loaded cabinets, etc...

In the same past year, I've used the SM7 for (partial list): micing bass amps, kick drums, lead male and female vox, guitar amps, front of kit mic for minimalistic drum setups, etc etc etc...

But there again, I've gotten to the point that when I start planning a session of some sort, I usually start thinkng dynamics or ribbons, and start going for condensors when the dynamics just aren't working....

I love how versatile these mics are! Especially the 57. I only own one, but it looks like i'll be grabbing a few more. The sm7 was a freebie, which is also sweet. Thanks for the info.