I've been wanting CS5 for the new Premiere Pro and After Effects stuff for quite a while now. Then, once I saw the Mercury Playback Engine demo video showing real time editing of native 5D2 footage (and other native HD formats, including RED 4K), I really wanted it. Granted, that was with a Quadro FX4800, but still, that's not all that expensive compared to other systems.

Go to http://cs5launch.adobe.com/ and click on the "Sneak Peek at the New Adobe Mercury Playback Engine Technology" link to see what I mean.