I'm pretty sure I've mentioned it here before, but, in case I haven't, let me say now that I absolutely adore Dave's Mapper. Look at this terrific dungeon level I created from several of the geomorph sets available through the site:
I like dungeon geomorphs. In fact, I think they're a nigh-essential tool in running a megadungeon-centered campaign. Like all such tools, they're no substitute for individual creativity or hard work, but they definitely have their place. Goodness knows I wish Dave's Mapper had been online when I started my Dwimmermount campaign two years ago; it certainly would have made my life easier at times.