My Microsoft Bluetooth Wireless Desktop 3000 works great on my HTPC. No issues at all. The receiver is well across the room.
Always had trouble with all of them that I've used for years and years. Once, long, long ago I had a logitech "trackball" RF remote that worked well, but nothing since then. All up until this Microsoft Bluetooth set. It works from the kitchen through walls, I've even used the keyboard outside the house (though exterior walls). It is equal in reception to my Snapstream Firefly RF remote (which is very good).
Even nicer... The battery life on this thing is astounding. The keyboard takes two AA batteries, and is very lightweight and compact. I use two of those rechargeable Duracells (or maybe Energizers, I have both) you can buy all over the place now. They generally work for around two months before they need charging. I just have a zip-lock I keep of charged batteries in my coffee table drawer. When I swap batteries, I throw the discharged ones directly into the charger. They hold their charge fine for a few months.
The mouse comes with it's own set of these same types of commodity rechargeables. It also comes with it's own little "recharging dock" pad-like thing. It works great. The mouse will start occasionally pulsing a red light when it is low (maybe happens once every two-three weeks) of moderate HTPC use. I just throw it on it's charger overnight when this happens (not all the time when not in use, always a bad idea for rechargeables) and it'll be fine in the morning for another two-to-three weeks or so.
The only thing I don't like about it is the stupid, weird Function-Keys. They are these weird "touch sensitive" bumps (not pressure sensitive, they seem capacitive almost). They stink for gaming, but wireless keyboards are never good for gaming (though otherwise, this one would probably work okay -- the mouse does). I use my Belkin Nostromo for FPS's anyway, so that doesn't matter to me. I wish they would make this exact keyboard, with a slightly more standard layout (put the Windows button back where it goes, thanks), and normal F-Keys. I don't really mind that it is missing it's Number-Pad, for a HTPC keyboard. I thought I would hate that, but I ended up not caring at all. It is like a laptop keyboard. And I'm used to the weird F-Keys now, so they're not that bad, just annoying that they did it purely for the "cool" factor (at the expense of usability).
All-in-all, I've been VERY happy. It was expensive, but worth every penny. Best Wireless Keyboard Purchase Ever (and I've probably owned 10 sets in all over the years).