Sennheiser Recommendations?

I wish to purchase a new pair of headphones. Sennheiser has been decided on as the manufacturer. There is some decent equipment in the equation, notably: an Audio Alchemy DTI v2.0, a Parasound DAC-1600 and a Melos Sha-Gold. My listening tastes are pop and rock. The models for consideration are: 555, 580 and 595. Money, though not determining, is also a factor.
go for the 600. It is like $150 used and good very close to the top of the line 650. I have it and don't have enough justification to upgrade.

It's not my favorite headphone but I like it enough to keep it.
Check out a web site called it is a very good headphone site with a lot of knowledgable people.
The 600's can be difficult to drive. I had nothing but problems with the Melos gear. I have the Musical Fidelity v3 and it is a perfect match with the 600's !
Aside from the recommended site posted earlier...I have the 650's. I'm surprise you prefer Senn's over Grado's...most rock listeners like the Grado brand for their bass/mid bass slam. I love my Senns but mostly for their detail...I sold a pair of Grado's that I wish I kept for listening to rock.

I've heard good things about the 595's but haven't listened to them directly. I agree that the 600's are the best bang for the buck. I too am using MF's X-Can V3 that controls the hard to drive Senns nicely. Be wairy of any headphone jack on components (even name brands) they are usually junk that is thrown on...Cary being one major exception. If you are getting an amp consider Ray Samuel's amps...I would have bought one if I didn't already have the MF.