I find it hard to separate Christmas presents from birthday presents in my mind, so I'm struggling a bit here. However the following (which were definitely all Christmas presents) come to mind:
1. The pet rock my mother gave to me when I was 22. Her choice of present showed that she was 'really on my wavelength' when it came to my daft sense of humour. (Alas, it got thrown out many years ago).
2. The table lamp that the three young boys who lived next door to my parents gave me in 1974 or 1975. They were very apologetic that they'd only been able to afford the base bit, and not a shade as well, but it was all they could manage from their combined savings. I was totally delighted with their kind gesture and I've still got the lamp (with a shade added to it, of course) in my living room now.
3. The 'old man' money box that three of the girls in my class gave to me in 1989. They were worried that I'd be offended by it but, again, I was utterly charmed. I can see it from where I'm sitting now.