Mouse: Logitech (loved the MX700, currently abusing my MX1000)
Keyboard: Microsoft (love the natural stuff, especially the wireless version)
Speakers: Klipsch Ultras for bass, Creative Gigaworks for mids and highs. Onkyo S760/770 for overall sound in a comparable price range.
Webcam: no clue, as I've never used one.
Here's another one:
Headphones: Audiotechnica or Sennheiser, depending on mood and amping
I just wish someone made a cordless keyboard (in natural flavor) that didn't have to be part of a desktop set. My old MS keyboard is getting a bit finnicky, and while I have a corded version, I'd rather have the cordless...but I don't want to pay that much.