Fitz is the ugliest thing known to man, I have some supervisions there and the architecture makes me want to cry. I don't actually know where Robinson is, I'll be honest... Clare cellars is meant to be good but I hear Clare itself is a little pretentious. Trinity and John's are something else, just because there are swarms of tourists around them and they are intimidatingly beautiful rather than cosy beautiful... can't say I'd ever really feel at home there. Emma is nice, and has the cheapest bar in Cambridge apparently. It's pretty academic and hence competitive, I suppose.
Just my thoughts...