Sorry, but the best I've had is the CF Felt Z frame i built up with Sram Red about 12 years ago.
For classic steel, I have VERY fond memories of a mid-late 70s Raleigh Super Course. Inexpensive bike with inexpensive components (Simplex), but it always felt good to ride, better than any bike before or after until I got the Z. If I get another bike (have 6 now), I think I'll hold out for a British bike with geometry like the Super Course, except top quality with top quality period-correct components.
A 96 Litespeed Classic I've had for a couple of hears is a close second.