The menu on the left-hand side is a bit plain. I’d throw a very simple gradient on there (not too much though, that would ruin the effect of the website!)
The color of the different "Zoeken" texts on the home page color greenish when I hover them. Looks like an opacity problem.
I would consider re-styling the “Geavanceerd zoeken” page. Currently some of the lines contain the label and the input on the same line, while for some others the input field drops to the next line. Looks a bit messy. For example you could make the search the width of the whole screen and than put the “Meest gezochte zoektermen” below it. That doesn’t have to be as prominent as it currently is anyway (IMO).
Also, I like € 5,- better than just € 5 , but that may be a personal preference.