Absolutely - The Book. You'll pay a bit more, but you get more instruction. It breaks down the basics, goes step-by-step through the progression and has a ton of tips.
Waketrix interests me (I've seen Waketrix TV on OLN), and does a nice job, but The Book just has more.
Others are cheesy, contain footage of random goofing off and don't show as many shots of riders riding the basics.
Check out the trailers for each of the DVD's at: http://thebookdvd.com/wakeboard.htm