You may never see the light of day if you try and read the entire Columns UI thread, so this most of the useful information for new users will slowly be filled in here.

Rather than blindly using someone elses config, it is best to get a grasp of the titleformatting language, so you can create personalised configs yourself. The language used in titleformatting is tagz; for more information see the articles below:

• Titleformat Introduction
• Titleformat Reference

$div(%_filesize%,1048576).$num($div($mul($mod(%_filesize%,1048576),100),1048576),2) MB

$ifgreater($div(%_filesize%,1024,1024),1,$div(%_filesize%,1024,1024)',',)$right($div(%_filesize%,1024),3)' KB'

In your colour string, use this code for the colour you wish to alternate:

$ifequal($mod(%_playlist_number%,2),0,<colour a>,<colour b>)

replacing <colour a> and <colour b> with your desired colours.