I've found Cooler Master's mechanical backlit for 60$, 50$ after a mail in rebate in a couple places in the first two minutes of checking prices. While maybe not "cheap" as in the Keyboard in the no name section at Walmart, it certainly can't be called expensive. Not for something you use more than any other device while on your computer. Anyhow, that's what I would buy over a non mechanical G15 or something similar from Logitech say - and I used all those types of "gaming" keyboards with my IBM clicky AT keyboard until the new mechanical gamer boards became available. It's not that they 're bad or anything, they just don't offer the precise accurate keypress a mechanical does, and CM's keyboard at 50 bux is cheaper than the G15 type gamer boards as well, yet a much better typing experience, by far.
And, for the record, I'm typing this on my home entertainment system with....the same 19 dollar MS optical keyboard/mouse combo mentioned. It works, but when I go to my desktop and type on it for 3 seconds, I remember just how crappy it actually is.