Birdsnest!!! I can't praise them enough. I ordered something a Friday night, received it the Tuesday (and I'm in WA), beautifully wrapped, free reusable bag, and handwritten thank you note. Top notch brands and easy to use website - for instance you can search according to body shape and other functions.

Offtherunway - limited items, but heavily discounted. For instance i got my Siegerson Morrison boots $425 down to $197. Very good if you like high end designer peices.

Freez - Good for mid range designers, having a huge summer clearance at the moment, but i haven't bought from them yet.

Shoebox - for shoes, great range, some unique shoes you don't find in the general stores and members discounts.