First of all, Corsair K90 does not have ALL keys mechanical (programable and media are rubber domes), and its an RTS keyboard.
That beeing said, its the one i aim to buy as soon as i can. There is no comparison from the corsair k90 and other keyboards (especially if you want back light.
Stelseries 6gv2 is a cheaper optin if you can forgo the macros en leds.
I do have to warn you, K90 keys have a crappy paint coat, so you might want to get a few keys for replacements.
And answering ANtiZig's question: You never had a girlfriend mad at you? Well, now think that you are a keyboard that she is mad at... the keyboard was lucky that only the space bar got destroyed.