The best place to download WC3 maps is here:
http://www.epicwar.com/
It's where I get all of mine. To be honest though, I have the most fun playing those arcade-style games, like Uther's Party. Pretty much any game in which you can find a fun bug to mess around with your friends is fun.
If you like DotA (and I do not >.>), you may want to try playing a game called EotA (Eve of the Apocolypse). You may also enjoy such games as Battleships (which includes spin-offs like Battle Tanks).
I personally enjoy more team-based games (yea, DotA has teams, but it's not all about working as a team, really) you may like the incredible game SWAT, which has a website here:
http://www.redscull.com/swat/readmeafter.html It's an amazing game with more levels than are apparant, but it's really hard and requires a lot more strategy than other WC3 maps.