The task bar is horrid. it is designed for people who cannot read or they are stupid.
"Click the folder icon, Click the blue "e" icon." Sounds very childish to me.
Other then that I like the speed is slightly better then Windows Vista Home Premium, However they have removed some features that I use. Like the mini player in Windows Media player, and some of the NT backup features the people at my work use.
I shall give it a go when it is in it's final incarnation. Great thread. The word needs to get out there about Windows 7, so more people can improve it.