I'd say the Audi RS6 sedan, for it clean, balanced proportions.
I'd also say the DA & DC platform Integras
Good design is timeless.. think of the original Z, the BMW 3.0CSL & 507...
And as nice as the Mazda 6 and new RX-8 are, the multiple lens headlights and taillights are already kinda wearing on me. The Altezzas on the new Evo 8 are a crime IMO...