SnapZ Pro X 2.0 (shareware, Ambrosia Software, $29 for still capture or $69 for still + motion capture)
Advantages:
1. Much more flexible than Mac OS X's screen capture. Still capture works very well. (Motion capture should be evaluated for performance with your system and your application.)
2. If I remember correctly, it doesn't artificially cripple itself when the DVD Player application is running.
Disadvantages:
1. Likes to put up a modal display that delays the system for two seconds or so at startup time. Removing the application from the startup item list and running it yourself is a workaround for this.
2. The vendor uses a registration scheme where the program only accepts registration codes for 30(?) days from the date of issue. If you pay for the program, then use it for a year, then do a clean install of MacOS 10.5 ("Leopard"), you'll probably find SnapZ X Pro telling you that you are an "unregistered user", and refusing to accept the registration code from your initial purchase. To be fair, you can request another code from the vendor, and they'll look you up in their registration database, and send another one out -- if they're still in business.