For boots, I would buy new. Every boot feels differently and a size 9 in one company could be a 10 in another. It's best to go to a shop and try out many different types to see what feels best to YOU. Plus they will conform to your foot...you don't want to wear something fitted to someone else.
For boards and bindings..yeah, you could get with used but it seems that everyone wants top dollar for their used stuff. So buying used over new doesn't really save you all that money...and then you have to worry about how the equipment was treated, if the buyer is legit, etc..
Personally I would buy new and this is the perfect time to do it with all of the crazy sales going on. I take it you're a girl by your name/avatar..if that's the case, you'll have even better luck since the female stuff on sale takes longer to sell out (better chance of finding the board/bindings you want in your size). I was looking at sale stuff for my girl and was amazed at the selection compared to what's available for guys.