Logitech isn't the only one showing off a new HTPC remote these days. If you haven't heard of Gyration yet, you should check them out. I've been using on of their in-air mice for several years now in my living room and it's one of the best things I've bought. They've just announced their latest product which looks like it could force my old one into retirement.
My old in-air mouse is just a simple mouse that you can wave in the air and have it move the cursor. It has your regular two buttons and scrollwheel just like any other mouse. However, the new Ultra R4000 Remote has all of the buttons you could possibly need, and even an LCD screen built-in.
You can use this remote to control anything from your home theater system, to your Media Center PC, and even use it as a regular mouse similar to their previous mice. It can operate from up to 100 feet away, so unless you have a huge room, you won't have any issues with connectivity. Look for this to show up sometime in the fall for $199.95. You can add one of their wireless keyboards for a combo price of $249.95.