I've been happy with Logitech for mice (Revolution, MX-1000, Mediaplay) and for the Harmony remotes. I'd have to say that I prefer Klipsch for speakers though. I've also been quite happy with external HD's from OWC's Mercury Elite AL line.
I don't have a lot of non-Apple accessories, I guess... but I would have to go with Griffin Technologies. They do a great job of making stylistically compatible items.
(I think my whole list of accessories consists of... Griffin EarThumps x2, iTrip x1, Lajo's skins for iPod - don't use anymore, iBook, and iMac, and a Tucano Second Skin...I guess you could also count my Be-Ez LeBag; the only mouse and kb I have are Apple, I have no hubs, I don't use my Epson printer anymore, etc.).