BUT, and this is a big BUT, having multiple personal projects does make you much more marketable to potential employers.
If you don't have a well known University or a well known company on your resume, having a stack of personal projects that show you're constantly learning, that you're passionate about the programming and that you love what you do can mean the difference between getting a request to interview at a start-up vs. getting put in the "pass" pile of resumes/profiles that internal recruiters have to look at.
This especially holds true if you work at a large, enterpris-ey company (IBM, VMWare, Goldman, Delloite, etc.) and want to attract the attention of, and get a job at, a venture funded start-up based on our experience at DeveloperAuction.