I am probably odd in that I hate shopping online. Absolutely hate it. I need to be able to try something on and being 100% sure it has a place in my life before committing to it, plus I like the entire experience of being able to build a relationship with a SA, go to a boutique and look at the items in person, have the experience of being in store...
My current favorite websites to browse and plan out future purchases are Hermes and Bergdorf Goodman, but I use them mainly for reference and to go in with an idea of what I am looking for. I do my actual purchasing in store.
If I do purchase something online, it is usually novels from Amazon.jp if my local Japanese bookstore can't get hold of what I want.