For the most part, the Classics are actually must better representations of the cartoon designs than the G1 figures. But for me, they just can't compete with the awesomeness of the Alts/Binaltechs. Those are just great, high quality, sophisticated updates for grown-ups.
Having said that, the Classics Starscream is really what got me back into toys as an older fella. The design was so spot-on, and a quantum leap from the original toy.
I also really dig that Skyfire/Jetfire. When he first came out, I couldn't believe that Hasbro was able to do the cartoon incarnation such justice.