Hey guys! I currently upgraded to Mac OS X Lion and i'm really happy to have done so! So far i'm really happy with the new os and its new features! I haven't completely used or tested all the new features but i'll take my time and run through all that! The whole track pad has changed and i kinda miss the multi touch gesture to switch to exposé a little bit though! However it'll take a little while to get used to the new trackpad features! Anyway, the point is that, I think Lion comes with Quicktime 10.1(501) and it doesn't open .mkv files! Also there are some .avi files it doesn't open and Quicktime asks you to open these .avi file with Quicktime 7. The other .avi files play perfectly on Quicktime I've already installed Perian long ago. That's the only problem i've encountered so far! Do any of you guys know how i can fix that? Thnx!