"Manage Applications" is a little more graphic-y and appears to give more detail about running applications (CPU used, number of processes and services running). I also don't remember free/used memory being quite so obviously displayed.
I'm thinking the move from phone to SD is a little easier now, but I never did that before since I have over 2GB of application memory free even after loading LOTS of stuff, so I don't know the UI all that well.
GPS lock appears to be a lot more "continuous". When running apps that wanted GPS lock frequently (Sensorly, for example), the GPS used to blink between red (no signal) and blue (signal good). After Gingerbread, the signal seems to spend a lot more time in "blue". I'll test that with Google Nav on the drive home - it occasionally got "stuttery" under Froyo and my location would update in jumps rather than a continuous flow of locations. It seemed smoother when I tested it but I was walking so I might not have been able to see the difference. It never really interfered with anything I needed to do - GPS updates were available every few seconds - but it was mildly annoying.
Google Talk has voice and video capabilities now. This is great, despite the fact that it insists on using the REAR-facing camera - at least I can use it to voice-chat with people on GT and not use my phone minutes, and my wife reported that (over a moderate 3G connection) the camera image quality was quite excellent if a little "jumpy". So if I'm in a pretty spot I can at least give my videochat partner something prettier than my ugly mug to stare at, and it might be useful for diagnosing problems (where I want to send the image of the thing I'm looking at rather than me). Still sucks that they couldn't get it right, but at least it's better than Froyo (there's SOMETHING there, it's just not perfect yet).
More widgets appear to be available in the HTC widgets section. Not that I ever use any of them since I'm on Go Launcher, but hey, it's an addition.