Pretty sure I should do both.
1) If you have a job the HR person deems you as more attractive as someone wants you. Similar to a relationship, when you are dating, all the other girls want you.
2) If you have a job, you can throw around a funny number, ask for more lieu time, vacation time, and basically control your interview process.
3) If you have a job while applying to a new one your resume doesn't show employment gaps which you have to explain in the future.