Let me start by saying I promise I did my research before bringing the following questions to anyone, so I've pared them down through my research over the last month to a couple priorities here. Just notice that if you can't answer the first question, you may be able to at least contribute a little to the second and vice-versa. My questions are as follows:

*Based on the info I provide below, what might be my best headphone purchase?

and

*Because I think I'll be purchasing a Lexicon Lambda Audio Interface soon, will I also need an Amp (like the Filo E3/E5/E7/E9) and/or a DAC for best sound or will the Interface take care of that work? Also, might you recommend a different Interface for that price?

The necessary info: I've not been producing very long at all, but what I spend the majority of my time working on is house/dubstep/downtempo, all of slightly deep/abyssal/totallydarktimeslikeathousand varieties, on a Mac in Ableton Live. My current headphones are some Sony MDR-V600s (I know, I know) that I did a quick mod I found on the head-fi.org forums while doing this research and they're not so terrible anymore! But I want to start hearing my music the way it'll be heard by those who listen to it, so I need an upgrade but don't need monitor-type fidelity here. (For that, I'll probably purchase another set of phones based on what I learn from this go-round, but for now I'm just keeping it simple and getting one set to listen and produce.) I'm looking to spend anywhere from $100-300 (preferably closest to ~$200-$250, used from a good home is fine). In the phones I'm looking for right now, sub-bass is key, though I love a good mid-bass kick, and club sounds are lovely, but not important. I am, however, willing to make sacrifices to reduce a little bit of prominence of most bass-heavy-headphones' V-shaped-ness if not too sacrifice-y. So on with the options:

• Sennheiser HD25s are a serious contender just because they're recommended everywhere, though I'm worried that their "all around" greatness isn't good enough to give me what I want to hear in terms of depth
• Ultrasone 680s or the 780s seem to be a good choice for their bass, but I've heard it can get muddy, and with the depth I'm looking for, that's a serious worry of mine. I want my bass in my face, but I want it defined as well
• Denon's 2000s to see if they're worth the extra cash on top of the other two.
• I've done a little looking at Beyer's stuff, but it seems those are a little out of my price-range, unless someone's got a better understanding here. As always, it's open for discussion.

I'm up for suggestion of alternatives, or even links to online videos/reviews/comparisons, but as I said, I've spent the last couple weeks trying to work this out on my own and what I've found hasn't really done the trick, so I'm looking to generate some new feedback here. I know that "sounds good" is absolutely subjective and testing would be the best way, but I sadly don't have anywhere nearby or the time to check anywhere not-so-nearby for options.

Thanks for any and all responses and I hope to get this worked out soon! If I manage to pick, I'll post an update and let you know how I feel about what I got!

EDIT: Formatting