>> Well I'd expect MS will release a SP or hotfix for every new OS that
>> causes VFP to have serious issues, at least until 2015 or so.

No, that is not correct. Standard support only goes through 2009 (or January 12th of 2010 or something like that). In theory, Microsoft can issue fixes until then (although I would be somewhat surprised if they did), but during the extended phase (which goes to 2015) no service packs are released. Only security fixes, which VFP is very very unlikely to have.

Markus