Thanks to Whiskey's post...I'm adding my 2 cents. :)
Of all the romances I read, roughly 65% of them are historical romances. For loads of reasons...
...one of them being attire.
What sounds like a boring, mundane thing to love becomes a many faceted opportunity in a romance. Delicate shifts, laced corsets, beautifully embroidered over-skirts, bonnets, starched cravats, fawn breeches, and shiny Hessian's. Nothing quite compares to Regency dress.
The care, workmanship and pride in the wrappings of each character (and the delicious joy of the unwrapping) make historical romances special.
The trappings of clothing serve another purpose too - like the layers of an onion, most times the readers get to intimately observe the hero and heroine peel back the layers of themselves - their humor, fears, vulnerabilities and wit - finding what's underneath all the superficial is so much more satisfying than a quick strip - literally and figuratively.
A favorite historical of mine that knows how important these things are:
The rest of the series is pretty good too :)