<< There are a wide variety of video file formats for standard definition video. Is any one 'better' than the rest? For my purposes, I would define best as having either no compression or lossless compression of the video, regardless of the file size.>>
The Sony DV codec that Vegas uses is a very high quality codec and the reason quite a number of users adopted Vegas in the early days. You can test a codec by repeatedly rendering to it. Make a small change so that it doesn't smart render. I remember tests where the quality of the Sony DV codec was holding up really well after many re-renderings while other DV codecs (e.g. Microsoft) were badly degrading.
DV uses intraframe compression (every frame is fully described) so quality tends to be better preserved than say HDV or AVCHD which use long-GOP compression (only some frames are fully described).
If you need to render DV outside of Vegas (e.g. In VirtualDub) then the Cedocida DV codec is a good choice.
There are near-lossless or "visually lossless" codecs around such as Cineform, Avid DNxHD and Canopus HQ/HQX. These are similar to Apple ProRes, which cannot be rendered on a Windows machine. But really I wouldn't bother with them for DV resolutions. If you're talking DV then stick with a DV codec unless you want to squeeze out absolutely every last ounce of theoretical quality, in which case look at uncompressed or a lossless codec.
Of the lossless codecs, I prefer the UT Video Codec to either Lagarith or HuffYUV. This is because it is more responsive for playback, which makes editing easier, as long as you have "Optimize for decoding speed (Predict left)
" selected. Note also the check box for interlaced video at the bottom.
What is your delivery medium? I don't know of a plugin as such and I agree with John. I've not seen upscaling done in software as well as my DVD player and TV will upscale a DVD.
If I'm upscaling 4:3 PAL DV to 988x720p for the web I do a very high quality software deinterlacing with QTGMC in AviSynth and upscale with a Spline36 resize, followed by sharpening if necessary. Here's a simplified version of my AviSynth script:
#Frameserve out RGB24 with DebugMode FrameserverAviSource("d:\fs.avi")AssumeBFF()ConvertToYV12(interlaced=true)QTGMC( FPSDivisor=2, Preset="Slower" ) #25p outputSpline36Resize(988,720)#LSFmod(strength=500) #Sharpen if necessary#Open in VirtualDub and render to UT Video Code
You can see the results (post-YouTube-compression) in this video. Info (now a little out-dated) on how to set up this type of workflow can be found here. Be warned that it's rather complex. There are some other script examples in this thread. If Blu-ray is your target then a software DV > Blu-ray conversion done with a variant of one of these scripts would give better results than doing it in Vegas alone.