I wouldn't even consider a TT unless it was the current gen 3.2L, then I might be tempted but otherwise the thrill factor isn't there. BMW interiors are dull but well made, S2K is horribly dated on the inside as well, MX-5 mk3 is a very good car and I certainly wouldn't say no to the hardtop version, and the 350Z is a decent all rounder but the main thing that made me buy mine was the character of the car. I felt that the others lacked that, certainly the Germans.
Don't forget the Boxster as well, silly cheap now and fantastic cars, certainly a better drive than all of the ones you've mentioned (including the Zed).