[warrenpchi]

  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.  

  FWIW, I listen to my fair share of electronic music... and most of the open cans I have (K701 excluded) handle it fairly well.
 

  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. 

 

[Claritas]

  That is definitely a good idea. I've been casually looking around the Chicago area but haven't come across a place that sells audiophile headphones.  I've seen some places that aren't too far if I take the train, just haven't had the time to get out there.

 
Audio Consultants has three stores with listening spaces. They sell Grado, Sennheiser, Shure, and B&W. The Evanston store is the largest. If you're interested in a particular model (e.g., HD650), call before you go to ask if they have it on display because they all have slightly different stock.

 

[ZokharaFi]

Look into the Sony MDR-XB1000's and Audio Technica ATH-ES10's. To my knowledge either would suit you well. I have had experiences with the Sony MDR XB500's and they were the hardest hitting headphone's I have owned, with decent soundstaging but I would imagine the 1000's (2 steps up) would be a world of difference better. Do some research on them, you might start here: http://www.head-fi.org/a/headphone-buying-guide# ...coincidentally both of my recommendations are in there, under the Upper-Mid Range drop-down.
Hope this helps, & please let me know what you decide on!