I've been using a Logitech diNovo since they came out. For the most part I love it. Its nice and compact, and the media control buttons are nice. I don't like keyboards with a ton of extra buttons, and this one has just the right amount. The price is a little steep, but it has come down a bit. It was $250 when I got my first one. Newegg has them for $155 now. Its also very programmable.
The one issue I've had with them is reliability. I'm on my third one (its now called the diNovo Media Desktop Laser). Two times the keyboard just died, and one time the media pad did. On the plus side dealing with Logitech customer service has been great. Each time they sent me an entire new set (keyboard/mouse/mediapad) in the retail box. At no cost to me (no shipping charges, and I didnt even have to send the dead stuff back). So while I was not happy that something would seem to die after about a year, their customer service really made up for it. I've had my current set for around a year now. Hopefully they worked out whatever the issue was (this is like the 2nd or 3rd revision) and it won't die anytime soon.
Though even if it does if their customer service is the same I know I'll stay pretty happy with both the diNovo and Logitech. I would definitely recommend them.