Peter is absolutely correct, any number of sites for purchasing fonts, loads of fonts are also bundled with various graphics & word processing software, lots of free (legal) fonts in the public domain. All I've ever purchased & downloaded work across all Windows software incl Vegas. In short , we are spoilt for choice. Suggest Google "fonts" & check out the first 20 pages returned
Just a side note - fonts with sharp pointy things (serifs) look like crap on video. The compression just can't handle the sharp points and they get really fuzzy.
and only install fonts as and when you need them. apparently win 7's pretty good (about 1,000>1,500 fonts), but too many MAY slow down your system, dependent on ram.
this might, of course, be obsolete information (i'm obsolete after all), but sorting through too many fonts is a PITA anyway ;-)