There are two ways of going about licensing WordPress theme, You can License under GNU GPL or you can make your own license. Most of the big brand WordPress Theme Creators like WPMU Dev license under GNU GPL and then make you pay for the download. You could also do it where the download is free or you need a license key to activate the theme. Just remember, if its under GNU GPL, it legal to redistribute the theme without your permission. So if you have to pay for it and then someone gets it and gives it away for free there is nothing you can do, unless he claims he created the work. If your selling them on Theme Forest check there FAQ and T&C's for anything about this, some places tell you what to license it under.
You could go the path of creating a your own License or you could use Creative Commons which is stricter than GNU GPL. You mentioned other components having there own license, if they are all one license then it may be an idea to stick with that license.
Sorry about the long answer, but in Short, People tend to use GNU GPL and pay for the download. Hope this helps. All of answer is from what I learnt while I was creating a theme and needed to license it but also from looking at license's for other themes.