I use ISO recorder which is a really nice, lightweight tool to burn DVD's and CD's for data storage; this tool just hooks right into the OS and it is found in the right click secondary menu. It also gives you the ability to create ISO image files as well. As far as burning music, i just use the Windows Media Player and i find it to be a vast improvement over WMP11. Also, i really like how Microsoft got rid of that stupid 2 second delay in between tracks when burning songs onto a CD.
I mainly use what is convenient and familiar to me. I can't burn DVD's from my laptop which is my personal computer. I can't really say what software is good to burn a DVD for movie viewing and so i can watch a movie in my DVD player. If anyone has any suggestions on some really good, free software, i would love ot hear them.