This question was triggered by this section of DVK's answer on Is Viktor Krum a good wizard? :
Hermione liked him enough to actually go out with him somewhat seriously. Since this is NOT a Hollywood romantic comedy, I'm going to make an assumption that Hermione's personality is that of a typical nerdy know-it-all girl; and nearly 100% of those that I have known (and I've known plenty) were almost exclusively into guys who had intelligence.
To which I commented that she end up with Ron Weasley. DVK replied with this:
Ron is the best Wizard Chess player in the entire series. Just because he was a lazy student, don't make him not intelligent.
I remember him playing chess only in the first book, but I don't remember him showing smartness anytime after that, did he?