This is a really tough one!
TTM -
Betty White - Signed a photo to me and my dog & cat and also sent a handwritten letter {love}
Sarah Thomas, Jean Fergusson & Robert Fyfe from Last Of The Summer Wine all sent signed photo's and handwritten letters. Possibly the nicest cast of any tv show!
Martin Sheen - Sent a signed photo, signed my dollar I sent for postage, wrote "Thank you for a lovely letter" on my letter and wrote the return address on my sase.
IP -
Henry Winkler - Basically this guy was awesomeness personified

When I met him at Memorabilia he looked at me and went "Boy aint you pretty!"

(I assumed he was talking to the person behind me until I saw that it was a bloke

) He made me give him a hug and kiss & wrote on my photo "I'm so happy to meet you"

I met him again later on and he remembered me. He said "My darling has come back to see me!"

and he wrote on my second photo "I'm so happy, twice in a day and what a hug!"

He's a charmer {love}