The best and workable very free choices are these:-

1) download using 'keepvid'  - the idea is not to use the urls at the top of the page but the ones on the right where it says "video url"
                                          - copy paste this in "keepvid.com" and click download

2) mozilla provides a pluggin called "downthemAll" which works very well to accelerate downloads... you can either right click on  keepvid.com download button and "download link with downthemAll" and the mp4 will be there in a jiffy if you have good b/width

3) use vlc player --- it can play anything ... Even on an iphone, it can play avi(s)/divX(s)
     VLC can also convert to any format you like.