Quicktime may update a lot, and it probably does suck for Windows, but in Mac OS X, runs smooth as velvet, at least most of time when you don't load 5gb avi files. Windows Media Player sure doesnt (in OS X)
Not trying to flame Windows or anything, I actually use both OS's, but I tend towards the Mac side when doing things like converting movies or browsing the web. Windows has me won over with games...


