In most instances you would be better off executing a holographic will (a handwritten will- in YOUR own handwriting and signed by you) than you would using a kit will or one made up by an unqualified individual (ex. notary, paralegal). To make a valid will, there are some very specific things you must do- the laws are fairly specific in this area.
If you're in California, I'll give you a legal fill-in-the-blank will for free- just call.
I'd rather my clients, friends and fans have valid wills than leave behind a mess for their loved ones.