I guess that the question is what is the end result that you are trying to keep "the best quality" encoding for (playing on a computer, playing on HDTV--DVD or Bluray, uploading to the web, archiving, etc)
High Bitrate = High Quality.
(Do not confuse "memory" with "file size")
High quality= big file sizes.
You choose a rendering option based on your end requirement / delivery.
( Bit of trial and error involved for you to get the quality you want and the file size you are happy with.)
cheers, im actually going to put them on youtube, so is there a specific quality needed? they are HD when i
am editing them and id still rather not lose the quality if i have the choice
There are YouTube presets in the export options. Use one of those.