I'm 20 years old, my system:
DIY GR-Research AV-3 mains painted scarlet fever
DIY Dual Adire Audio Tempest 214L tuned to 15.4hz powered by 250W each.
Rotel RB-870 100 watts per channel separate amplifier
Altec lansing ACS56 amp powering JBL S38s for surrounds
I use my PC for the audio/video processing, it has 7.1 pre amplifier outputs (currently using 4 though) - Hercules gtxp
Pioneer 106S DVD player and 19" Cornerstone P1460 monitor
Cables by Acoustic Research, Dayton Audio, and Radio Shack Gold. Speaker wire by Carol superflex from home depot.
I have four 5" thick fiberglass 2'x4' acoustic panels in my room and am currently building four 16" diameter 4 foot long ACS type bass traps.
You can see some pictures of my HT at the bottom of the page here
I have over 10 gigs of mp3s I listen to a majority of the time, while the other 20% is for movies. I have spent about $1,800 total on everything audio in my room. Most of it was purchased used off of auctions or built myself.
Lets just say I don't have your average multimedia PC speakers to play my mp3s through winamp.