Tomas, I've arrived a bit late since you already bought a webcam. Still, it might be worth mentioning that
a wide-angle webcam is best for guitarists in order to capture what both hands are doing without having to angle oneself towards the camera or sit further back.
I snatched the Microsoft LifeCam Cinema HD went it was offered for sale. Its regular price is now what was my "sale price". I think it's excellent and I also like how it handles colors. It's not as good in low-light as its competitor from Logitech but that's not an issue in my home office.
Below is a comparison between it and the Logitech Quickcam 9000 Pro. There have since been some new entries from Logitech to the webcam market.