If you can find a Debian image without a crap tonne of nonsense installed on it, I'd go for that, but I'm pretty biased towards Debian. Arch is good for getting exactly what you want on it and nothing more, if you haven't played around with BSD, it would provide a good opportunity to so you can make up your mind as to whether you prefer it or not. Not sure how much more 'exotic' you could go without being unable to accomplish everything you want.