[Damien]

If you can get that eBay one then that's the pick of the three. If you miss out on that then I'd probably just get the YPT200. The YPT300 is nice, but if she doesn't really get into it then that's $100 that you could have saved. And if she really does get into it then she'll be ready for an upgrade in 3-4 years anyway. Those prices seem to be RRP as well.

The Yamaha website doesn't list Touch Sensitive keys as a feature of either the 200 or the 300, so I'd be checking that out first. If that's a main upgrade of the 300 then that's what I'd buy for a first electronic keyboard. My first Casio wasn't touch sensitive and it made it very hard for me to get used to that feature once I upgraded, it also makes it just that much harder to then switch between a real piano and the keyboard.

Electronic Keyboards feel and play very differently to real pianos, they also sound much different. If she's already learning the piano then perhaps you should take her shopping and spoil the surprise. A musical instrument is a very personal object and I know that I would always want to play an instrument myself before I took it home.