Oh, interesting topic alert!
I have signed photos of Peter Leslie and the female black presenter (Diane Jordan or something) from Blue Peter. I wrote to them in the late 80's saying I was upset at receiving a chain-mail letter from them attempting to break a world record and the only thing that would pacify my tears is signed photos and a Blue Peter badge.
Ok, now it's time to come clean. I didn't receive a chain letter, my Mum forced me to write it a fake letter. We were going to London a month later and the badge enabled free entry to some tourist attractions! Hahaha, she's a fraud but she's fab.
I have a copy of Goldfrapp's first album, Felt Moutain, signed by Alison Goldfrapp. "Dear Ian, all my love, Alison xxx". For those who can remember Richard Last/themeparkphreak, his step-autie-in-law (or some ****) is Alison Goldfrapp and I pestered his Mum for ages to get it signed and she did!
My prized signed item is an offcial B&H Masters (snooker competition) t-shirt signed by legends Stephen Hendry, Steve Davis and the late Paul Hunter. I won it in a radio competition about 8 years ago. I must get a proper frame for it. I've subsequently collected the autographs of Shaun Murphy, Marco Fu and Ronnie O'Sullivan.
Nowadays, I think photos are "worth more". Ok, not financially, but grabbing a photo next your somebody famous is worth more sentimentally. I've got a few photos of me with Matt Le Tissier and one with somebody who was on my recent connecting flight between Vegas and Atlanta...but it's too embarrassing to post on here...
And like Ben, I regret not getting a photo whilst rubbing shoulders with the famous. I wish I had one taken with Mel C at Paultons Park last year.