I, like Don, have been using Lion since its release and loving it. (Though just for the record, I put it on my personal machine. We’re still BFFs, IT!) I’ve found features that I was specifically waiting for (e.g. Resume, tricked-out Finder) and ones that I hadn’t expected (e.g. Actions in-line in Mail such as Delete, Forward, etc.).
Another such feature that I didn’t expect was the new “Natural” scrolling in Lion. Because Lion incorporates many of the features prevalent in iOS, the way one scrolls is backwards different. Scroll down, and your mouse goes up. Scroll up, and your mouse goes down. I understand that motion on my iPhone; not so much on my iMac.
Thankfully, the fix is easy if this is bothersome to you as well! Just go to System Preferences > Trackpad and uncheck “Scroll direction: natural.”
UPDATE Since this was featured in Kibbles & Bytes, I received a few responses which pointed out that if one does not have a Trackpad (either no laptop or no Apple Trackpad), the Trackpad preferences will not be visible. To that I say, you’re right! If you don’t have a Trackpad attached, you’ll find the same option in the Mouse preferences.