Well personally having had Windows machines for years I've now converted entirely to Mac.
I still use MS Office and if I really need to use a program that isn't available on a Mac I simply run it on Parallels (the only program I actually run regularly is Front Page)
I do find that with Mac's I just get on and use them - I was getting a wee bit fed up with all the security issues and constant downloading of upgrades for virus scanners and the like on my PC.
But I suppose that as Mac's become more popular the security issues will grow and then I may make the leap to Linux....