Generally any part of the electronics used can possibly affect playback. Ideally you would want to calibrate each video source. If you watch video from both the PS3 and the computer then you would probably want to check the playback of each device. Some electronics, such as cable or satellite, may not offer test patterns, and in that case one way to handle things is to calibrate for a reference output like commented in #2664.
With the PS3 you could download the AVCHD and burn the image to DVD media. In that case I consider it safe to assume that Sony has made sure the different video types allowed for Blu-ray will all match. By using the AVCHD you would have a reference for Blu-ray playback on the PS3.
With computers things may not be as simple, depending on the software used. With Windows there are certain issues that can show up from different containers or video types, depending on the video drivers or playback software. I'm not familiar with Mac, VLC, or color profiles to really comment about any possible issues in using different containers or video types from the ones you would typically watch with the computer. It's possible that VLC may not exhibit the sorts of possible issues mentioned in the series of replies to smokarz (start at #2651), but putting the calibration video through the same modifications as other video you typically watch might be a more thorough check than simply using the MP4 download to check playback from the computer.