I ran a search and this came up, I thought I'd bump it because this game is so awesome.
I'm pretty good at playing any of the towns, I have my own separate strategies for each, but overall I like to play defensively until I get my army built up to massive proportions.
Another part of my strategy that some people find odd is that I only play with one hero. I like to consolidate all of my power into one guy: armies, spells, artifacts. And once you get Fly and/or Town Portal, it becomes really easy to manage your entire territory with just one hero.