QUsers has tons of homescreens and most software that will run on the q will run on the dash so i look there from time to time.
At Howard Forums there are three forums to watch. HTC Forum, General Smartphone Forum and TMobile/Windows Mobile Forum.
Modaco Forums cover some good apps in their customization forum.
By far the most important thing to do is read the whole faq at htc, then start reading the forums. Using the faq and surreal networks get the phone app unlocked and slowly start adding programs that you think you need. Take your time and use one for a few days before adding another. This way you know if that prog is conflicting with anything on the phone.