Well, I'd imagine if you asked 50 people this question, you'd probably get close to 50 different answers! But since I have only had one amp with my 580's, I can only offer that experience to you. I am currently using a DIY amp called a CKKIII (or CK2III, or more technically The Cavalli-Kan Kumisa III ) as described here http://www.amb.org/audio/ck2/ . Paired with a Nforce uDAC fed from my PC through the USB port, I really enjoy the sound I hear with my 580's. I feed it with lossless FLAC files through Fubar2000 and the quality is excellent.
I picked up my CKKIII here in the For Sale forums for $150 but I generally see them run in the $150-225 USD range. Recently the uDAC's have been seen in the FS forums in the $60 range (I use the 1st gen uDAC and that is what I've seen being sold here) so that seems real close to your budget's range. The uDAC also has a built in amp as well as a DAC, but I wasn't ever satisfied using it as an amp. As a DAC it functions fine for us low budget folks.
My rig is definetly on the lower end of the audiophile's scale make no mistake, but honestly, I have never been disappointed with my low budget setup.
Edited by Dojomoto - 11/20/10 at 2:52pm
