Yeah, it's a lengthy process. Give it about 10-15 mins.
Funny you ask, cos I installed CM 6.1.1 this morning after a Desire HD ROM had problems. This is not the first time I'm using it, and everytime I install it, I cannot continue using it beyond a day. Mainly cos I miss the HTC Phone application, which is awesome with Facebook, Twitter integration as well as smart dialing. Plus, the ROM does not have A2SD+ so that all my apps are installed on the SD. I'm actually on a ROM frenzy right now and installing different ROMs to suit my needs.