There's always the risk of disappointment in meeting your heros. Of course, them being with us helps!. Jeremy Wade would be my choice, as he has covered such a wide range of species and techniques. He always states that he is not a proficient fly angler, but his results beg to differ.
I always wished to meet Richard Walker, but that was not to be. Again I missed Peter O'Reilly by hours on the Galway Weir, having his two books (and a pen) at the ready.
There's a few Posters on here that a twenty-four period studying them together would be interesting, connected by the love of fishing and yet .....