First of all, here is what I use:
Vegas Pro 13
Usually handle these formats: mpeg4, mp4, mov, avi.
Every time I format my computer, there is always a huge chaos in the proccess of making the codecs work properly with Vegas. This forum has the best information about this matter, and some users states clearly that installing codec packs is the worst way possible.
So here is the question: if istalling codec packs is bad, where should I look into the proccess of installing just the right codecs? (consider the formats I've mentioned)
Default Windows install + Windows Updates +latest video drivers + Quicktime + Avid Codec pack + Vegas. Then leave the system alone. Convert your footage into professional codecs that Vegas comes installed with, if you require some high bitrate reason for other codecs. Switch to .MXF for editing and deliver in .MP4 or .wmv or whatever you require.
For example HDCAM-SR, SR-lite, or XAVC-I would be more stable in Vegas than say operating with legarith or other similar kluge codecs. Quality loss with those codecs is more perceived than reality, and the image issues probably stem from poor source material than the codec.
[Alan Lupatini]"So here is the question: if istalling codec packs is bad, where should I look into the proccess of installing just the right codecs? (consider the formats I've mentioned)"
MOV and AVI are not "formats" themselves, they are just containers for hundred of codecs. What you should do, is as you encounter MOV or AVI files for which you do not have the codec installed on your system, use a tool like MediaInfo for AVI or the Inspector Window in the QuickTime Player for MOV to determine what codec the video requires and go the the manufacturer of that codec and download and install it. That's all you need to do. This will give you just the codecs that you need.