Brilliant. One of the best (the best?) purchases that I have ever made.
It was a close call for me between this and the Samsung Galaxy S. The Samsung has inbuilt storage (which is better than having them on an SD card) but:
* I prefer HTC's Sense Android theme to Samsung's TouchWiz;
* I don't like that the Galaxy looks like an iPhone;
* the Desire runs Android 2.2 Froyo, whereas I think the Galaxy S is on 2.1;
* the Galaxy S comes pre-installed with Swype, which is an excellent way to "type" on the device (and you can only get on the Desire by joining the Beta programme);
* I understand that the Samsung updates through a Windows program (I use Linux), whereas the Desire updates itself beautifully over a WiFi connection; and
* the Desire was quite a lot cheaper and EKing included an 8GB SD card anyway.
At the current low prices it is a no-brainer. I use it for Facebook, email (work and personal), calendaring, watching movies on the bus, GPS mapping for OpenStreetMap and heaps more -- and it isn't much more than a normal good phone. I would choose this phone over an iPhone at the same price.