http://en.wikipedia.org/wiki/Shure_SM57 ShureM57 is very popular lot of people use it
I went with what is called the E609 both pretty similar and price range just personal preference for me.
and I 2nd the Snowball mic, and I really like the 3 “modes” it has. You can also look at other condenser and dynamic mics, because if you decide to get serious about recording or just upgrade even at home a lot of it comes down to personal taste/opinion and what you like.
Good luck. Might wanna read some stuff just get an ideal of what it is all about….
http://homerecording.about.com/od/microphones101/a/mic_types.htm