I've been lucky with Skydome 90% of the games i've gone to have had the roof open. Only been to one game with the dome closed and I thought it was boring with the dome closed but with it open and the tower overlooking everything its pretty good.I went to the new Mets stadium when I was in NYC, it was impressive. Skydome is a terrible venue (have gone to a ton of games there). Fenway isn't great in the modern sense, but it's awesome to go once and experience it. Wrigley is on my list for the same reasons. My favorite MLB stadium I've been to is actually Progressive in Cleveland.
Was at Chase Field in Phoenix, great stadium but really small concourses, not wide enough. and because it was also Opening Day the place was packed.