Just got off my butt and played around with one of the 75's I bought at Office Depot earlier in the summer. Got out my drill and Kramer modded the grill cover, then put on a pair of fake Sennheiser MX200 pads and the Parts Express headband.
These things are really, really surprising. One place that they seem to excel that I didn't expect: electronic music. A lot of people mentioned that they were good for electronic in their reviews, so I'm not sure why it was exactly *surprising*. I'm listening to Daft Punk's Discovery right now and these budget bastards make the album sound extremely fun.
Call me crazy, but I actually like the parts express headband! I like how lightly the drivers are placed against the ear. When I had the portapros, I felt that they clamped a bit too tightly (which also affects the sound). Another thing I like about the parts express is that when I wear them around my neck, I completely forget they are there and they are not very noticeable.
Whatever you do, don't get the sportapro for the headband - I find it way to small for my head (and I don't have a huge melon). But slap the sportapro (ie portapro) drivers on the parts express headband (after doing the kramer mods), and then you've got an awesome thing going :)