Since Mac became Intel-based, it has been able to run Windows XP on dual boot (OS X), kind of like the one we are used to in Windows. At some computer and electronic sales last year, Mac machines and laptops have been demo'd using both OS's. As for Vista, it is said that the best machine currently to run it without upgrading to maximum souped-up specs is a, uhm, Mac : )
There is Flash for OS X and Dreamweaver MX for it, too : )