There is no "best" post-production/video editing software. It always depend on the guy infront of the PC!
You can make great movies with the windows movie maker or iMovie on a mac. If you know hwat your're doing, the software you do it with doesn't really matter that much. Of course there are some things, that are easier in more expensive software packages like Final Cut or Avid, especially if you deal with special effets. I really like Adobe Premiere Pro because of the great integration with other Adobe Products.
For editing, there's also Sony Vegas, but I haven't tried it. However, I heard good things about it.
For VFX-Work, I use After Effects, but things like Smoke/Flame, Apple Motion or Combustion are other software that basically do the same!
If you're more into 3D, there's Maya and 3DS Max, but also XSI, Cinema 4D and even Blender, which is free.
As I said, in the end it comes down to personal preference. You can make good movies with all those programs! Just choose the right one for the job and the one you like best. Don't think you need to spend all your money on an Avid system just because the newest blockbuster was cut on Avid!
