I am running a fully stable (except camera) fast MyTouch HD ROM on my HD2.
This ROM is amazing, it has a badass skins chooser, it has different "modes' like kid mode, where it turns off the dialer and stuff so they can just play games.
The UI is nice and smooth, looks great, the ROM in general is insanely fast and smooth.
It also has some nice widgets that come, since it is a Sense UI skin, you get the HTC widgets and the flip clock and stuff.
Here is the ROM link, I am linking so you can check out the screen shots on the first post, it is so sick.
[UPD][BUILD][19.10.2010]Mdeejay Glacier Sense v. 1.0.1 [kernel: hastarin R7.6] - xda-developers
I love this ROM so far, I am sure more devices will get a port.