The
Best Web Browser on Earth has a few extensions, or Add-ons, that can download any media from any site (MediaPirate, DownloadHelper, Magic's Video Downloader; I use DownloadHelper). When it comes to flash animations, they can extract the flash video from them and play them as they were played without user interaction (eg. no games, but youtube vids: yes). Matter of fact, the add-on MediaPirate was made just for this purpose.
Further, you can extend firefox to show your download's progress in the status bar (
Download Statusbar :-)
I know VLC can now play FLV files, but I'm not sure if the FLV format is native in other media players, but if you wanna travel with your downloaded movies, then you just need to convert them to MPEG or AVI files (which are supported by almost every computer in
the world)...
Riva FLV Encoder 2.0 can do this (i haven't personally tested it though). if riva doesn't do it for you, ffmpeg (for linux) might...
YouTube used to have three(?) links off to the right-hand side of the video area that were for downloading the content in three different formats (windows, mpeg, and psp; or something, something else, and psp; one of them was psp though..). It's a shame they took that away.