1) Boot times are still the same as Vista
2) Simple file operations take longer under Windows 7 than in Vista
It will be awhile til Windows 7 catches up with XP's compatibility. Do you really want Windows 7 to have the same compatibility? It will also mean getting the same virus infestations as well.
Your best bet is buy new version of your favorite software if you can afford it. On the plus side, the new version will have more of the bugs work out of it.
You see Vista's security is built on a new file system as well restrict low level processes (such as Starforce application) that take over your system.
I can still run older application like DVD shrink because it does not secretly steal memory resources like Starforce.
Or you can just learn linux?