Headphone Amplifiers

Current apartment living dictates that listening to music via of headphones is the only available form of critical listening (a euphemism for loud music)? I have a set of Sennheiser Hd-580's. In the the past, I have reached the pinnacle of perfection via a Melos Sha-Gold. Present monetary considerations prohibit any such expense. So, I'm looking at the Creek OBH-11 and the various Musical Fidelity headphone amplifiers. Any other brand and model suggestions would be appreciated. About $200.00 dollars is my spending limit. I prefer rock and pop music.