I recently bought the Microsoft LifeCam Cinema HD as my cheapo £5 unbranded webcam's mic had gone and the whole thing was generally a piece of rubbish.
The LifeCam HD is excellent, up and running very easily, unfortunately it seems you have to use an install CD which puts software on your system, but it's fairly un-intrusive and allows you to add effects to your webcam on the fly (much similar to photobooth on a mac) and record video or take photos.
The webcam itself is wonderful quality, which is one of the problems I always had with Logitech, they always just looked/felt cheap to me. It's very small and gives great video/sound, and is easily clipped onto things with a sort of moldable stand that can be wrapped around awkward shaped monitors (very useful to me, my Samsung B2230 has a curved back which made clipping my old webcam on a PITA).
Couldn't recommend it more. Hope this helps.