I'm in a similar spot, I'm looking at the 11/12 Wrx and Ms3 to purchase at the end of summer. I'd love to test drive either but I don't know anyone at the Mazda dealer who has the speed sales in the area, and there are no wrx's for sale within almost 500 miles >.< Guess I might have to wait for the 12's regardless on that.
The GTI is underpowered and looks like every other car that VW sells, in my opinion. The SI has too much of a boy racer appeal without proving itself as capable enough compared to the other cars in the segment. Also, Honda fannies are the worst, as the OP already noted.
I'm looking at the Wrx for how they hold their value, best performance in segment, awd, utility (coming from a miata the Wrx has 100% better performance and a vastly superior cargo capacity), and great looks.
The ms3 looks great in my opinion, I've heard great things from friends who bought them re: performance and drive quality, better mpg than Wrx.
Honestly you can't go wrong with either choice, and I can't wait to get into one of them come August =p