A couple of Ice Cream Sandwich ROMs have popped up for the Desire. I've been on and off watching them for a while, but never really bothered with them as I know the Desire won't officially get an ICS release, so I've not bothered flashing one. Recently though the majority of the problems have been cleared up bar one or two minor ones with USB tethering, so I decided to give it a flash.
The particular ROM I flashed is this one. It uses a nice touch screen installer, so it's easy to customise what you want/don't want installed. Once up and running it is surprisingly smooth for my two year old Desire. It's not as smooth as the GB ROM I used, but that's expected.
I do love the interface changes. The new app drawer looks nice, and the new colour scheme works really well. The contact book has had a nice overhaul. If you link your contacts up to their respective social networking profiles their contact page is filled out with photos from it. Facebook integration is seriously lacking with this version of Android though after the whole Google-Facebook dispute, but there is an app that can fix that, which I'll make another post about.