I've been told by many folks that this Logitech diNovo Mini Keyboard is one of the best HTPC keyboard options available. I haven't reviewed it yet but will be doing so.
If you want one, this is the best deal I've seen ever. Just head to Dell using the link below and enter the 30% coupon code 739PKVBXNL?Z3L
Logitech diNovo Mini Keyboard $95.19 ($135.19 - $40) after coupon 739PKVBXNL?Z3L
found via MissingRemote