As a young audiophile and broke college student I wanted a pair of headphones that sounded great and were relatively inexpensive; these Grados were perfect.
 
They have a full, detailed sound and the high frequencies are very crisp. The bass could be a bit more responsive but after some modification should be up to par.  I also like that there are a lot of ideas and tutorials on how to mod these.
 
The downsides however, are that they leak sound which make them difficult to listen to in public (both because you can hear outside sound and others can hear your music), the vinyl headband and plastic cups make them look and feel a bit cheap, and the stock pads make the ears sore after a few hours of listening.