I agree that if your hardware configuration (RAM, CPU, etc) supports Vista, it should support Windows 7 (the same bit version).
The only issue you may have with Windows 7 is that a lack of drivers. From what I read, Windows 7's driver availability is very good as a lot of users seem to have no issues, however, each computer / model of computers has a different motherboard and motherboard components, and you never know if everything will work for you. Let along, if there's a program that you definitely need, I would at least research on whether that particular program has been reported to install and run smoothly on Windows 7. Reminder - Microsoft says we shouldn't try this on computers we need for work, school work or whatever else. The program is meant to be for TESTING. Basically, it will be a matter of luck whether things work as beautifully as some other people have reported.
You can certainly keep or delete the Vista recovery partition when you install Windows 7 into the partition that is currently used by Vista. I am personally not sure if there's any point in keeping the recovery partition because is the recovery partition able to restore your computer to the original facotry settings even if the Vista instllation itself no longer exists? Is it something that you have to run from Vista to utilize? Or it is like having an OS disk that you can use that partition from the boot to initiate a clean install of Vista? It would be moot to keep that partition if the parittion cannot be used for a clean install and all you can do with it is more like a repair install to original settings from inside Vista, as Vista will no longer exiist...... Does anybody know what HP's recovery partition is about?