First, I am NOT endorsing this company selling this, and have not bought anything from them. Unfortunately this keyboard seems to be discontinued, so neither Amazon nor Dell has it.
It's a membrane keyboard...but it's MUCH, MUCH better than 99% of keyboards today, which seem to be competing with notebooks for how terrible they are.
This has a normal key layout, normal feeling keys when you press them, and just a great feel to them. The Microsoft 3000 I'm typing on now is utter garbage by comparison, as is a Logitech I've also tried.
My only complaint with this model is the volume control (which works in Windows XP, Vista, and 7 without extra drivers) sort of broke off on mine...I think using two normal buttons for volume up/down would be better.
Other than that...this is 100x better than anything I can find actually being sold in stores today. I don't know that it quite compares with like a mechanical Keytronic Dell keyboard from the late 90's (which was on par with IBM stuff or Apple's old keyboards...Apple's gotten progressively worse too, to the point they're actually trying to sell notebook chicklet keyboards as desktop boards!)
So...anyway, if you can somehow find a new one, it's a great keyboard.