Ahhh, now ebay is an entirely different prospect, and one that I wasn't considering.
Are they used, refurbished, or just... ebay? If you can find yourself a decent keyboard with mechanicals, then jump on it.
I'm not going to talk about buckling spring keys, because I've never typed on them, and from what I understand, they're weird. But I personally use a Leopold, which you should be able to find pretty easily, as they're made in the UK, and they're built like tanks. I love mine.
As for the switches, it's a very personal decision. I personally wanted a non-clicky keyboard, and ended up going with MX Blacks - I absolutely love it for gaming, but even though it increased my WPM by about 20 almost instantly, it gives my fingers fatigue after typing a long essay - I would almost have gone with reds or blues for that.