I'd like to drive a 2.5L WRX. I found the 2.0 suffering terrible turbo lag and the STi certainly has no lag if your're comparing the two. Driving the STi I wondered why the 6-cogger as it's got lots of torque and good low-rpm boost, but the 6-speeds do make it a bit easier to keep the boost up, but that's only when you're really cooking. Really cooking in an STi means that you'll go to jail if someone with a badge is a witness.
I think the 06 WRX is now a better value at $36K now that it has the 2.5L.
There are used STi's out there, and if you're willing to part with cash, you can find them. They're not bargains, but since the STi customer is usually (the ones I met, anyway) quite well-heeled, the cars are well cared-for. $38-40K will get you into a sweet STi. It's not that far from the new price, but when you consider that a new STi will run well into the $50K's with taxes, PDI, etc. $40K isn't that bad for a low km example.