Have you taken a look at the Ideal Mindset, Decisive Action, Consistent Acheivement PLCs on special? Although I haven't taken any of them they sound pretty good and they're fairly cheap right now.
I have the Natural Brilliance PLC and I'm really enjoying it. I consider myself a newbie, but the N.B. program is an excellent way of breaking down your old behaviour patterns (or limitations). After doing some of the sessions I've found myself doing stuff that I normaly considered way out of my league, and enjoying it. I'm comming to the conclusion that the Natural Brilliance PLC could be a good foundation for any other PLC out there.
Cheers! 
