Goshi Wrote:OGG > MP3

Indubitably.

I say money.  Mainly cause I'm not the kind of person to buy the best stuff - IMO, not worth it.  You spend so much just for a keyboard which is a bit better.  I've been using some crappy $5 keyboard for years now - heck, all the letters are rubbed off cause I've used it so much.
In the end, when you're actually using the keyboard, you seriously won't notice that much of a difference.   Just save the money up for something more important.