Big can or worms, but here's a couple of pointers
A lot of people can't hear the difference between 128 and 192 but if you can it's huge, if you're planning on using these files to recreate CD's stick with 320 for the lossless factor as long as you're not worried about hard drive space, if you've got the actual source you may as well preserve it's integrity.
For compatibility I would recommend just sticking with the MP3 format if you can use it for the output filetype.
Lastly for the moment, "burning" and "copying" are synonyms in that sentence, however, you can burn MP3's either as an audio CD or as a data CD, leaving them as data you'll be able to fit a lot more on a disc, but it requires a specially qualified player, burning them as audio extracts the data and returns it to the original format so that the disc is compatible with pretty much any stereo or audio device.