I recently switched to MobaXterm [1] and liked it so much that I paid for the Pro edition. I also love how I can launch X apps on my Fedora dev VM and forward them to my Win7 desktop - I know should be able to do that with CygWin but I could never get it to work properly.
I too switched to Moba recently after trying just about everything else. Some of the things I really like about it over the competitors:
* single binary installer
* X server
* Tabs
* Automatic SFTP sidebar when connecting via SSH
* painless SSH-tunneling (I can never remember the order of arguments on the command line)
* dancing Tuxes
There's probably more things I haven't even discovered yet (which may be too much for some people, who just want a simple terminal emulator). It's not all roses, it has locked up a couple times on me, but thanks to tmux it doesn't bother me much.
[1]: http://mobaxterm.mobatek.net/