The Sennheiser PC 150 headset is supposed to be a very high quality headset. It is an older model, replaced by the PC 160 (Which I have on order).
I researched headsets thoroughly before I bought one, and Sennheiser's got all good reviews. I also own a pair of regular Sennheiser headphones for the podcast which I love (and I actually where em' during the day at work too. CAUTION: When you wear noise canceling headphones at work, make certain you have a rear view mirror in your cube).
There was some debate about 1/8" jacks vs. USB. Mac users beware of USB headsets, they don't all work with OS (like the ones from Sennheiser). I opted for the 1/8" jacks because in a pinch they can plug directly into the mixer for the podcast. I also plan to use them primarily for Skype calls and playing music at work. Oh yeah, if you've got a powerbook or other Mac laptop, be certain to get an iMic2 and don't be a dumbass like me and try to plug a mic into the line-in port, because, well, it doesn't work :)