My sources are a M-Audio 5.1 Revolution for my desktop, and a Cowon U3 portable that plugs into a PA2V2 amp. The Grados are a pair of SR80's (mainly for the portable) - my other pair are Sennheiser 555's (desktop only).
A humble setup, but makes me quite happy for what I'm willing to spend on that kind of thing for the time being
Are you into headphones?
That's cool! I used to browse head-fi for awhile. I was really hoping to get some Grados, but didn't have the cash at the time. All I have is a pair of Sony MDR-v6. They got a great range, which is cool for listening to music with alot of layers (i.e.: my fav, Devin Townsend
). I figure if I ever strike gold, I'll spring for the Grado RS-1's... but that might be years from now, lol.
Oh, and I also have some Westone UM1s for the portable setup: (Sony NW-HD1).