Thank you all so much for your replies. I'll expand my search to consider open headphones too. I'm definitely not a basshead, but I certainly listen to a lot of electronic music and rarely listen to much classical music.
Just wanted to make sure you were getting all the sound quality you can get.
After some additional reading this weekend, I'm leaning towards the Sennheiser HD650s. From what I can tell, they don't really do anything 'wrong', its just that some people prefer more emphasis in parts of the frequency curve. I don't know if these will have much bass impact, but I'm realizing that I don't want to give up a lot of detail and soundstage width just to chase a thumping subbass. Given that realization, I think I want a great all around headphone, and the 983 page thread on the HD650 seems to claim they are pretty good at everything, but not superior in many areas. Most complaints seem to be resolved when they are given a sufficiently powerful amp to handle the 300ohm impedance.
The HD 650 is a unit that I have a love/hate relationship with. First of all, I should note that you will have NO problems with getting adequate bass response. My complaint about them is that I find them to be dark, warm and a little wet without proper amplification. I believe the term I used to describe it was "vaginal." That's just my personal preference though. I know a lot of people find them to be just fine.