I was a bit sceptical of these when I first saw them and was recommended them but I'm not glad I did purchase them in the end. They are a significant improvement over my old Sennheiser HD201's! Works fine on Windows 7 (without the software installed)
I bought these for Skype, listening to music to avoid disturbing the house-mate and also the odd gaming session- turns our they're far better at the gaming and music than Skype! How and why? Because the design firmly shuts out extra noises from your environment, it does mean your voice seems stupid whilst talking on Skype (or when talking when gaming).
Sound quality is great - I've actually taken to listening to music on these instead of my speakers (which aren't exactly great anyhow). Possibly a bit bass-y at times but that could be the MP3's more than my music.
Microphone works well with Dragon Naturally Speaking, Skype and Mumble (not tested on anything else). Quality is good - no complaints about audio from anyone I've spoken to.
As to regards the USB nature of having to restart programs, I found this not to be the case IF you made a few changes - after plugging in, goto the Sound section in Control Panel - you then see a list of attached devices - if you set the headphones and mic to default device, the PC will automatically switch from speakers to headphones as soon as you plug in and unplug.
Overall, an excellent product and one that I hope to be using for a good while yet.