At work I drive my friends '00 Impreza 2.5 RS all the time. Its a sweet ride.
Its a rally car, just remember that. Speed wise, its about as fast as a Honda Civic Si (their sport model of the civic). There is a decent aftermarket for it and it has a extremely loyal following.
My friend hasn't had any major maintenece done on it yet, it simply hasn't needed it. We just got finished doing donuts in the snow (ya baby, in TX, its sweet!). The AWD system is extremely balanced, its a shame that Subaru won't bring the STi version from Europe over here.
The WRX is the Impreza with a Turbo. The new WRX coming to America this year is IMO ugly, but its fast(we're talking 14.2-14.5 1/2 mile times). They're almost as fast as a new Camaro Z28, but not quite up there. The older WRX's (00' and before) are sweet cars, if I could get my hands on one I would.