OK, uses for your 57...
Firstly, it depends on what you're working with other than the 57 (other mics, pres etc).
Violin and cello - probably not!
Drums - snare, like you said. Also can be good on other percussion, toms. Can use for kick but there are definitely better choices. And wherever you use them around drummers, bear in mind that they can take hits that would bust most chinese condensors right open. And you can use a 57 to hammer in a nail if you don't have a hammer around!
Bass - Probably not great for this either
Guitar - Yeah, it sounds different to a condensor on amps. But it sounds good, and it fits into the mix well. If it doesn't do it for you on its own, try tracking in stereo with the B1 and 57 in x-y or on different speakers (checking phase of course). Recording both lets you chose which sound fits the track best in the mix, or pan hard for large sound.
Vocals - you don't mention vox, but it's great on some voices.
There are loads of mics out there, and all of them are likely to sound better than a 57 on something. The point is that they sound good on lotsa things, and are very reliable. They don't have that condensor crispness (which reminds me of everything I hear on the radio these days), so they take a bit to get used to using if you're only using condensors. But different sounds fit together better than the same sound often in a mix.
I have 2 57s, and if I could swap one for a 421, or a 635, or whatever, I would. But I'd always keep one.
Steve