I have had this keyboard for 2 weeks now, and I love it to death.The backlit keys are a godsend for gaming in dark rooms, and the LCD screen is cool as hell.
People have already started writing plugins for the LCD, one of which I installed. It is a really handy little program that uses the LCD to display what Teamspeak channel you are in and who is talking.
The media keys do work with Winamp, and the LCD does display ID3 v1 and v2 tags.
Another nifty little feature that Logitech added was on the display option that shows CPU utilization and memory usage, the CPU bar graph is actually split in two for dual processor machines. My Athlon 64 X2 4800 shows both CPU utilizations, and it is cool that Logitech had the forsight to code in dual CPU utilization.
The tactile feedback of this keyboard is fantastic. It feels solid and well constructed, and having 2 USB 2.0 ports in it is a nice feature as well.
The switch to disable the Windows key is also very nice. The macro keys are fully customizable in any program or in the native Windows environment. The macro capture feature is awesome, because it allows you to capture macros on the fly in game or what have you, and the macro capture ability also lets you capture pauses and delays in the key sequences.
All in all I'd say this is the best keyboard I have ever owned, hands down.