I think none of the softwares you told will have any problem on Vista. Vista will be best for you since it requires less maintainence, for ex, XP is plagued with all the flash drive viruses, while they dont work in Vista. Almost 90% computers that i have saw with XP are infected with these, and you as being a student will share a lotta things using USB drives, you'll get mad soon with XP. Go for Vista, even if you fell that you'll need another GB of RAM, its worth it. Just make sure you do a full system update after installation, remove all the crapware that comes preinstalled by most manufacturers, and defrag you harddrive once a month (for that you can leave the system for a while, when screen blackout kicks in, Vista automatically optimizes the filesystem
). That'll keep your system in shape.
and yes, Vista has absolutely no compatibility issues with MS Office as well as playing MP3s. Many compatibility issues arise due to its security features which can be overcome using the compatibility settings or running the app as an administrator. Some updates had also been released that fix compatibility issues with certain apps, thats why i said to fully update your system after installing Vista and all other MS apps. That'll make sure great speed for you.
One more thing, when you boot Vista for the first time, you may notice a performance hit, but as you begin working with it, it'll improve on speed due to its SuperFetch technology. On my lappy, Vista runs at least 2x faster after 5 days of usage.