I mainly ask this question as a GM, because I want an idea of what I should be focusing on whenever I create my character sheets for others to use. Though I'm aware that the people who frequent the forums aren't exactly the same group of people who use the roleplaying system, the latter being the one I use.
Personally, whenever I write a character I like to focus on the personality more than anything. I don't exactly like character sheets that want you to list out every single little detail and quirk about your character. There's just no reason for it in my opinion. Listing out what your character likes and dislikes is one thing, but why do I have to list out a character's strengths, flaws, goals, hobbies, habits and fears? I much rather explore and expand on those things in a roleplay.
Though I can see how doing exactly that can benefit the roleplayer, as it forces them to know exactly who their character is, and that does definitely help whenever they're roleplaying, or at least in my experience.