I have the Eris. When 2.1 hits the Eris, for the first time the stock Android interface will look nicer than Sense. I have a feeling HTC is going to strip out all the nice stuff in 2.1 (the 3D gallery, the rolling app menu, etc) and make Sense look the same on 2.1 as it does on 1.5. Oh well, assuming the Eris can even handle all those fancy graphics (I doubt it) I will be using home switcher to bypass Sense and run stock 2.1 on my Eris. I've seen 2.1 on the Nexus and it looks amazing, much better than 1.5 sense. I really hope HTC doesn't screw it up and just shoehorn Sense onto 2.1 without changing anything.
Oh and it gets better. Google rolled out an update today to the Nexus phones....now 2.1 also includes Multi-Touch among other things.
I guess we Eris folks are spoiled since we've already got it. And seven home screens.