1) I would first recommend to perform a soft reset. This is done by powering down the phone, remove the battery for at least 30 seconds, replace it and restart the phone. This will clear the cache on the device.
2) Also clear all background data from the Sense application. Select All Apps > Settings > Applications > Manage applications > HTC Sense > Clear data/cache.
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First, I think everyone should be forewarned that clearing the data/cache from htc Sense will clear your custom layout on your phone (icons, background & theme etc.).
Secondly, I myself was struggling with the HTC logo & white screen everytime I went to the home screen or clicked out of some apps, so I thought it's only fair to share my resolution. I did indeed clear the cache & reboot the phone as mentioned above & after I finished resetting my icons etc. it was working fine, so I went to the web and started browsing (imgur!) & after 10-15 minutes as I click on the home icon, KABOOM the wait screen is back, which is when I realized that the phone cache just got loaded with cookies/data/crap which was causing this, so I went to apps/running apps & clicked on Internet & cleared the Data (it does clear the bookmarks as well, so prepare for that)now the phone works fine.
Bottom line is to make sure that the cache doesn't get clogged with data which will cause it to slow down. It's a hassle but keep it clean to keep it efficient.
P.S. I didn't want to root my phone while still in warranty (will get to that once i'm out).