Definitely my favourite in the series. It improves nicely on 2, which I also loved. I respect 4 for its attempts at trying new things, but it was very hit and miss. 5, on the other hand, sort of gave up and tried to copy 3.

I've got to say, however, that the expansions started what I found to be the most annoying flaws in the campaigns since, which is to say following heroes throughout the entire campaign. I liked the notions behind The Succession War and The Restoration of Erathia much more.