i was gonna agree with chris, buying used is a good option for the older high-end electronics. i was never into car audio when the 7909 was around, but i've heard good things about it. anyways, i like the 7949 from alpine. that aforementioned clarion is very classy looking, and has good d/a. i've got an older eclipse, 5303r, which i like. that nak 45z is nice as well, simple, and very good sq. and for sony, they had a c910 in their es lineup which also had the copper chassis, it was a good unit with rotary volume knob to boot. if you care to waste time on the 'net researching car audio stuff, i suggest
www.elitecaraudio.com you'll find a plethora of info there.