1)   Agile MPEG Video Joiner 2.0
Agile MPEG Video Joiner is the most popular video tool that join AVI/MPEG/MPEG/MPG/WMV/ASF/MOV... videos to a large one such as MPEG/MPEG-4/iPod/iPhone/PSP/Zune.... It merges multiple videos of different formats and supports so many output formats.