You want it, you got it. Erm, or you can at least ask for it. Google tonight has turned on Wish Lists in the Google Play Store.
The mechanism is simple. Find something you want in Google Play, and then hit the bookmark button on that page. That adds it to your "Wish List." We don't yet see a way to send that wish list to anyone, or to have anyone other than you pay for it. So basically you're making a list of things you want to buy later. Which is fine for now, we suppose. (We're totally going to spam Mom and Dad with this later, though.)
The really cool part for now is that this isn't just limited to apps. You can bookmark music, magazines, movies & TV or books. Anything that's in Google Play, you can add to the wish list. Perhaps we'll see more functionality announced in a couple weeks?