Drum Recording Handbook or Music Producer's Handbook, you'll find that most session drummers bring a variety of snare drums to a session. While the average number seems to be 6, there are some drummers that bring far more than that.
That's not to look cool or show off their collection, it's because the snare is the heartbeat of the song, and therefore has to fit just right with the rest of the instruments into the mix. Getting the right snare sound is essential to making the final recording and mix really pop.
Here's a great video from Pro Tools Expert that lets you hear exactly what different snares sound like on the same track. Which one is your favorite?