This is a Dynamic microphone.  It can be used in almost any setting.  I don't recommend it for Vocals in a Studio setting because you should really be using a quality condenser for that.  But, I was told a few times by a few different people that the SM 58 and the SM 57 are identical microphones with the exception of the Grills.  With that being said, I have used my SM58 on all sorts of gear including Guitar amps, bass amps (in conjunction with a Beta 52a), drums (snares and toms) and yes, even vocals (before I got some nice condensors).  With the exception of Vocals, this thing sounds great on everything in the studio.  There is a reason that Shure SM mics are the industry standard.  They are very clean and crisp and they can take a really good beating and keep on trucking.  As for live situations, these things are essential for any working band or venue.  I used to host an open mic for over a year and the venue had about 6 of these and they were dropped repeatedly buy clumsy or drunk musicians and every single one worked great the whole time I was there.  On top of all that, I asked the owner at one point when he got the mics and he said many years ago.  When it comes down to preference however, I always take my Shure Beta 58a and my BG 5.1 vocal condenser if its just me singing through them.  The SM 58 always rides along but the other two are just all around better/stronger mics.

OVERALL OPINION

One of the best things about all Shure Mics is the amazing warranty they have.  Even when its out of warranty, no matter what happened, or what condition it is in, you can always send it to shure with a nominal fee (about $35 to $40) and get a brand spanking new one in return.   Besides that, this mic also gets props for its ability to take a beating and still sound great.   For the price (under $100) and its durability, this is a great mic.  The precision and quality of the sound is excellent for a mic in this price range.  I have used many different condenser mics including Samsons, Audix (also very nice), and behringer and the only one that can share the stage in my opinion is the Audix.  The rest are just wastes of money.  Yes, I would definitely keep a few of these around all the time.  You never know when you might need one and you can always be sure that it will live up to its reputation.