I recently read this on Nate's blog and I couldn't agree with it more.
I agree wholeheartedly with this mostly for 2 reasons:
1. If you follow a program designed by someone who knows their ****, it will probably always be better than what you can come up with on your own
2. You'll learn new things and you'll be forced to do things you'd probably stray from if you designed it yourself
Actually in respect to point 2, the main reason why most people want to change programs before starting them is to avoid the stuff they are not used to or feel uncomfortable doing.
Check out the blog post here - Stupid People Write Their Own Programs
Whats everyones thoughts?