Also, the Logitech Z2300 are a damn fine bargain for a 2.1 system. I've heard several complaints about the Klipsch ProMedia 2.1 subwoofer, so I'd definitely go with the Z2300.
In fact, I have a pair of Z2300's; I've had them since Christmas. I can tell you one of the most subtle, but well-thought out features is the fact that when you plug your headphones into the volume control, you can turn off the sound but still hear from the headphones, in case somehow your headphones get unplugged in the middle of the night you won't wake everybody up. That's a damn fine quality, but I don't know if the Klipsch have it or not.
Other than that, there's no treble control, but there's a bass setting on there. Cool little blue LED light, the buton hasn't stuck for me yet, the wheel works wonders with how precise you want your sound, and the subwoofer is tremendously powerful. I'm sincerely scared to go up any higher than I have before, because the walls literally rattle. Screw the reviews that say that there's no mid-ranges, that's all BS. The sound on these things is incredible, not a single note is missed. But, they really shine when you watch movies and play games. I don't know what else to say... my friend has the Klipsch 2.1 set, and he and I both agree that the Logitech wins. But in the end, it's up to your friend.
Hope that helped.