I can recommend the Sony MDR-7506 & Monoprice 8323 headphones. In fact, both sets have surprised me (the Sonys have been w/ me a while) in value & quality. I was one to go after some more premium models when I started using DAWs, but after testing, I always stuck with the Sonys. They are of a sturdy build, comfortable, & have replaceable ear pads (had mine a few years but not needed replaced yet.) The sound is quite natural & uncolored compared to your avereage retail phones.
The Monoprice 8323s are just gems. There's no way around it ... unless you have a large head. Mono's 8323s come with 2 cords that are detachable at the left driver (one is a few ft of thin gauge wire; other is twice as long and heavier gauge non-coiled.) These are of a cheaper heavy plastic construction & I do open/close them cautiously as to not jar the pivoting mechanisms. It seems like they could break fairly easily if not careful. The drivers, on the other hand, are hilariously awesome! I did a lot of research on these & some other potential budget studio/audio products Monoprice offers. I can't help but notice that these things are so similar to their closest mainstream counterparts it's almost suspicious. For example, they have studio monitors that bear the same construction down to screw patterns, drivers, and crossovers as other popular models offered by top brands in the industry. Nonetheless, they sound incredible. They are on par with the sounds of the top studio cans manufacturers & have identical drivers to boot.
Sony MDR-7506
Pros: Priced under $100; Great Sound; Historical quality; Replaceable ear pads
Cons: Somewhat quiet; maybe too flat/natural sounding for some (could sound quiet w/o amp)
Monoprice 8323
Pros: Priced under $25 (perhaps better if you sign up w/ them and get new customer bonus) ... yes $25!
Fairly comfortable (unless your dome is large); Unmatched sound within $50-100 more; Detachable cable at phones; Seriously....
http://www.monoprice.com/Product?c_id=108&cp_id=10823&cs_id=1082302&p_id=8323&seq=1&format=2 $25
Cons: Plasticy; Non-replaceable ear pads
Edit: Adding that the Mono's aren't great for isolation (others can hear them in the same room)/ The Sonys aren't bad at all, but in quieter situations can be heard.