For whatever reason (unknown to me at this point) ClearType is turned off on (at least my) HTC HD2 by default.

To turn it on, and improve the quality of your text/reading – simply do to the following:

Go to Settings, either via the Start-menu or HTC Sense.
Tap on Menu in the lower-left corner, and select All Settings.
Tap on System.
Tap on Display.
Tap on the tab ClearType.
Tick the box and tap OK in the upper-rightcorner.

I personally recommend restarting the phone once you have turned it on.

Enjoy the improved text/font rendering!