I love the 1910s and 20s. Would love to have worn Poiret silhouettes and draped myself in Fortuny velvets. An Edwardian walking suit, a Delphos dress and an opera cape -- those are my ideal garments.
I also have a soft spot for some 60s details: T-strap flats in shiny bright colors, exaggerated collars and cuffs, corduroy anything. And a few "before the 60s were the 60s" looks: madras wrap skirts, stitched-down pleats, shift dresses, olive with pale blue.
Nothing from the 30s, because you needed to be a slender reed for all those bias-cut dresses and little suits à la Wallis Simpson. Nothing from the 40s and 50s, because you needed a waist then. Although some sculptural 50s looks -- swing coats with huge cuffs and sweeping collars, anything by Balenciaga -- are awfully appealing.
I admit I don't get the retro appeal of the 70s at all. To me they meant unflattering earth tones (rust, chocolate, camel and beige were supposed to suit everyone), too-short bellbottoms and itchy pantyhose. As for the rest of the decades, I'm eternally grateful that stretch fabrics and discreetly elasticized waists were invented.