One thing that might help when in W7, re-building the set of apps previously installed under XP, would be to migrate the whole XP instance to a virtual machine elsewhere, in practice my MacBook Pro, which has Parallels 6 under Mac OS.
Then, while installing apps to the new W7 instance, can do a side-by-side comparison with the virtual XP instance. The only unknown is the Microsoft activation/licensing issue – could it “clog the gears” of this proposed process? Presumably I need to transfer the activation(s) to the XP virtual machine. But could the W7 Upgrade process itself absorb the XP activation, crippling the XP virtual machine?
Only one way to find out, and that time is not now…