I don't have a single favourite but Simonesato is up there, as is ajmfashions (mostly trendy/young stuff but there's always a few gems - I got a Derek Lam dress for $150 from her a few months ago, and I would have paid a lot more for it).
Shona_mac is another one.
"It's now very common to hear people say "I'm rather offended by that." As if that gives them certain rights. It's actually nothing more than a whine. 'I find that offensive.' It has no meaning; it has no purpose; it has no reason to be respected as a phrase. 'I am offended by that.' Well so fucking what." - Stephen Fry