Just went back to 10.6.5 and Safari 5.0.2.
Now the HD video plays fine. I still have all the same apps (dropbox, evernote, etc.) installed and no issues now.
I was having issues playing Hulu Desktop files in HD without choppiness, but that is not a problem anymore. They are playing perfectly.
Not sure if it is 10.6.7 or Safari yet, but I'll try to find upgrade one at a time to test.
That's good to hear. I was gonna do that myself but I'm a little worried another problem might pop-up and besides, updates are supposed to improve not disprove.
I wonder if some other people are experiencing the same with 10.6.7.
BTW, the demo units at the Apple Store were all running 10.6.6... no wonder why the run flawlessly.