I'd vote for the wrx. Especially the 2009 wrx with increased in power, and ton's of potentials. I'd check out NASIOC.COM, its a subaru forum where you can find out all the good / bad things about the wrx.
From my experience ( I have an 03), the wrx has a glass tranny, so if you have on doing ALOT of "very spirited driving" I would think twice and go straight for the STi or even an EVO. But if you want something thats a DD with good power and great handling and occasional "spirited driving" the wrx is more than enough car.
Bad thing about a subaru besides the tranny (again this was the issue with previous wrx models, not sure how the new ones are) is that people often mistake it for a diesel (at least that what mines get mistaken for)
The SS on the other, is... well ehh. Im biased, as I hate the SS or the neon SRT4, I think these cars are GM's way of trying to get a piece of the pie ( the tuner world) without really thinking about it. I'm look at the styling, its ugly as hell and makes it more ridiculous with the stupid looking wing that simply does not flow the body lines.
But one good note for the SS, a few years back on the speed channel they did a challenge, and took the SS and other "tuner" cars and had "tuners" built them for racing specs, the SS of course was backed my GM while the others car were done with private tune shops. The SS won the challenge, but thats after ever piece of the ecotec motor was re-vamp.
My vote, wrx, its what makes a subaru a subaru.
If that isnt good enough check out this video, This should make you wanna buy a SUBARU
Subaru Impreza by FORMAT67.NET on Vimeo