I love browsing online and seeing what's new, what's in stock.
I just hate not being able to try anything on. Fit is super important. :P So if you don't open a retail outlet, I find it hard to order anything other than accessories. Rather than a general "sizing guide" you could make a unique size chart per item? It's a lot of additional work, though, so I doubt that'll happen.
The site looks clean and professional, if not too white. Maybe try a light gray background color, to make it easier on the eyes to browse? Being able to filter by brand/category/size is nice.