One of them - one I'd been really keen to see again - was this, which I'd received as a present back for my tenth birthday, I think. Some time ago, anyway. It was with (albeit not actually in) its box. On returning from the employment agency, In got the bag with all the piece in out of the car, sat down, and assembled it. (Is it wrong that I feel quite a sense of pride from what amounts to just following the flipping instructions..?!) The instructions weren't actually with the set, but I was able to download them, from the site I just linked to, onto my iPad. That made for quite a surreal experience (I'm sure my younger self would have loved the thought of sitting down to assemble a Lego model using some futuristic space age technology…).
(Am particularly happy to have the set back in light of the fact that it is presently going for £SILLYMONEY on eBay.)
There are two or three other sets that I'm quite keen to see again, including this, which was the basis of Benny's Spaceship, Spaceship, SPACESHIP!