J.-
It's interesting you say this! Last year when my stepdaughter was six she got the Fur Real Friend Butterscotch the pony. She played with that thing for 30 minutes. That's it! The pony was $300 and it was big! We had it in our basement for the last year, she's never talked about it or asked for it since. In fact, I had a recent post about selling it on ebay.
We've been working hard at teaching her that she does not get everything she asks for, or everything she wants. If you know she won't play with it, then it's NOT worth the 30 minutes of smiles followed by the year of ignoring it. And then YOU feeling like you just wasted a lot of money.
Also, you buying it and then selling it when she's lost interest is teaching her to be disposable with her toys and not be happy and USE the thing you spent a lot to get her.
I try to buy her toys that I know she'll get use out of. She ask for Barbies and Webkinz all the time but truth be told she plays mostly with arts and crafts. She has so many Barbies and Webkinz and she doesn't use half of them.
Kids at that age also don't know what's best for them, but YOU do. My stepdaughter was only mildly excited about the scrapbooking kit I bought her but the the thing she plays with the most often...the scrapbooking kit! She's always making something with it. The Webkinz she plays with for maybe an hour once a week. Same with Barbies.
I know you want to see the magical look on her face, and she'll have that no matter what.