Thanks for all of the replies, this is really helpful
To clear up a few things, I will be using these headphnes at home and possibly with an amp. Right now I just have a Fiio E5 to back up my HD25's, but I'll take any reccomendations if anybody thinks a certain amp is necessary or goes well with certain cans. As for price, the $350 that the DT990 and D2000's call for would be okay if they're worth it. I'll also pay extra for a good amp.
To be more specific about what I'm looking for, the main thing I'm looking for is soundstage, and comfort. The bass on the HD25's is nice and punchy, but if possible, I'd like a little more warmth and natural sound in that area. I'm not sure how to describe it, but I think you could say that I want something less analytical in the bass area.However, what I don't want is an overpowering or muddy bass that would make listening to rock unpleasant. For example, I have a pair of in-ear headphones called Atomic Bass that sound awesome for Daft Punk / deadmau5, but If I put some Red Hot Chili Peppers on, I can barely enjoy the melody at anything below full volume because all I can hear is bass. I'd like to avoid that issue.
As for the Beyerdynamic headphones, does anyone have any recommendations between models and the ohms concerning the above criteria?
Thanks again for all the help so far, I really appreciate it!