Hey, everyone. I'm currently in this place; I own a Cobalt Co9... it's a really nice dynamic mic with a good, open high-end and very decent and clear low-end. However, I own an SM48. It doesn't have so much of a clear top end, and has a sharp bump in the upper mids. It's pretty much useless for vocals (NO amount of EQ gets a sound close to what I want).
 
The only use I have had for it was when I was recording my brother on cello- I needed to get more bass n' body so I put the SM48 near a sound hole, and the Co9 near the strings for the highs and more cleanliness. I didn't have to do much in post beyond boosting the lows a bit more, and it sounded AWESOME.
 
So in short with the SM48's characteristics, what other uses are there for this mic?

You might have started to realize by now that one or even two mics are not enough...this is just the tip of the iceberg. If you're like most of us I see more mics in your future. You know how the SM48 sounds. The short answer is that you can do anything with an SM48 but the question is, How will it sound?
If you don't like how the mic you have  sounds on your material, that usually leaves only a few options. You can attempt to change the technique to get a better sound. You can attempt to change the source, or you can go mic shopping :)

I guess if it works well on the cello, then look for other instruments that have a similar range or timbre and try it out on those. It's trial and error with mics, you find some that have specific applications, others that will work well on lots of sources. Can't say I've ever used an SM48 but it sounds like you've hit on a mic that will give you great sound for a specific set of sound sources.

Haha, I wouldn't actually have a problem seeing it off...
I feel like I don't actually record enough sources to make it so worth keeping! But I'm gonna begin exploring muti-micing a lot more soon, so I guess I'll see what is to be had there. 
I'm certain that soon I'll be needing to use a lot more mics and more creative techniques with multi mics, so I guess it's good to really get a feel for it now.