Does most people use multiple video editing software or just one?

[Toysrme]

you can do it one of two ways.

1) upload beyond 1080p video, at which youtube allows streaming of the original file
2) recognize youtube transcodes with avisynth and x264. by using x264 to encode your videos, it can be tweaked so that youtube's copy of x264 looses very little on its transcoding pass

it also depends greatly on the video content in question:
contrast
edges
colors
motion
play havok with video codecs. especially motion. the less motion, the better.9

just on the video end for a minimum on great quality you want to upload
4mbps 480p
11mbps 720p
24mbps 1080p
doing so can make a large difference at the target bitrates youtube will shoot for

the last little key is not using crap software & codecs. if you're using anything less than an h264 video codec. you're giving away a lot of quality. (this means you, WMM people using the world's worst video codec in the last 15 years...)

[conbones]

Another great video editing program is meGUI with the avisynth plugin, the only draw back is an extensive learning curve but its free so you can't really complain

[Toysrme]

its not editing, it's frame server using avisynth that can transcode.

give staxrip a try. its quite a bit more flexible. you may like it better.

[BSF_Zappi]

Final Cut Pro X - I think I use 5% of the things this software can do. But it's better to be the limiting factor by yourseld, than beeing angry about reaching the limit of a tool :-)

[Glenstr]

I use a few, but mostly Sony Vegas. I have Corel's inexpensive video studio pro (3 and 5), it's pretty easy to use but a bit buggy. I was using 3 quite a bit but got tired of it crashing randomly and it's inability to handle mp3 files for sound, so I tried Vegas, which has a steeper learning curve but is SO much better and more powerful. Then I finally gave in to the nag emails from Corel and did the upgrade to 5 when it was only $40, mostly because it comes with the mercalli stabilization I wanted to try out. It's better than 3, but still not comparable to Sony, and Sony's consumer level products aren't much more $$ than Corel's are, and way more powerful. I do like the Corel (paint shop pro) photo editor a lot though, and it was part of the upgrade bundle so the VS5 was kind of a throw in. I also picked up premier elements suite when it was real cheap at amazon, but haven't even tried it yet.

Sometimes though, I'll even use Movie Maker Live, if I want to throw something together real fast that has minimal editing, for example a time lapse.