Is a 30 GB SSD a sufficient boot drive for Windows 7 Professional with XP mode?

"well, a fully blown Windows 7 Ultimate installation requires much less than 10 GB, but you'll have to allow for 'growth' (WinSXS folder), you can also disable hibernation if you don't need it, this will free up a great chunk of disk space (the equivalent of your physical memory).

if that's not enough, you can rip unnecessary/unwanted components (e.g. drivers, languages, etc.) from your installation disk using vLite (this can reduce the installation size to less than 2 GB, ex. pagefile).

so, with a little tweaking, 30 GB should be good enough for what you have in mind."