Let's just assume that Apple knows _exactly_ why they've priced the iPod mini at 249$ instead of 199$, shall we?
1.) They know people will buy them because of style.
2.) It gives Apple more money per iPod mini sold.
3.) Probably, quite probably, the mini-HD isn't as cheap.
4.) There's R&D costs involved.
Why should a competitor at the same price be a reason to lower the price? Apple offers more in a better package. I'd say, they could even charge 259$ for the iPod mini.
I'm also quite sure that Apple _will_ lower the price in a few weeks/months time and add either a lower-end (2 GB) model or a higher-end model (when larger capacity HDs become available in that size).