Anyone knows of any good virtual tabletops to use?

I've been playing with my friends for a while, and we began using Roll20 as a virtual tabletop, so that we could use a more fluid combat (with space movement and such). Problem is, Roll20 really sucks sometimes, at how slow it is, not to mention it has the nasty habit of sometimes turning my maps blank, making me have to refresh the page, and wait another 10 minutes for the add on the front page to end.

So, anyone has any good virtual tabletops that they use or that think they are good for PN?

I think I know of some, let me check, I know there are ones you can download like Vassal, which just needs a plugin for the game you want and it can run it. But I'll be checking.