It helps that the protagonists are likeable (unlike Matthew Broderick and Maria Pitillo in Gozilla
, a film I wisely forgot about until now) and that the movie never forgets to have a sense of humor about itself (unlike the crippling seriousness, for the most part, of 2012
and what I've seen of The Day After Tomorrow
And, again, I can't stress the importance of practical effects enough versus the unimpressive and at times unbelievable CGI in Emmerich's last two disaster pics.
Of course, nostalgia also plays a factor for me, since I first saw the movie (in theatres) when I was eight. For a while there I was convinced it was the best movie ever made.