I too am saddened by his passing... A great body of work by a man who knew how to entertain.
I think is says a lot that people of my generation know him as Batman, but that later in his life, he was still very actively working.. But with my kids (who are now 20 and 16), they knew him only from his work in animation (Fairly Odd Parents, Family Guy, etc...) and were surprised that he was the original Batman.. They have no point of reference going that far back.
I'm glad he was able to do the '66 animated movie.. It holds an even more special place in my heart now. RIP, sir...