I'm going to differ with the posts above.
I find that using a hand meter gives me a much better understanding of exposure issues than most of my cameras' built in meters. When I apply that understanding and actually think carefully about the choices available I usually end up with better results.
It is important to understand though that it is primarily the ability to use the hand meter for both incident and reflected readings that makes it more versatile than in-camera meters.
The Sekonic L-208 appeals to me, due mostly to its size and price, but I would suggest instead a meter that also offers a flash meter function - something like the 308 or a Gossen Digiflash (which I have).