Cadbury's Freddo Frog I loved these. My dad used to bring me one home each day after work. I used to be all over him when he got in, searching through his suit pockets for it. To this day every time I smell, let alone taste, Cadbury's milk chocolate I think of it.
Domino Rally I had a Domino Rally set and thought it was fantastic. I had a lot of patience so I guess I didn't mind all the set up time for a short pay off. What I also particularly remember was that the box was absolutely jam packed, it was really difficult to get everything back in there, which made a change to most things which rattled around in oversized flashy boxes.
Action Jacks They were a great cheap alternative to the M.A.C (Mobile Action Command) figures from Lesney/Matchbox. Here are a couple of links:
Action Jacks: http://www.geocities.com/lukemeadley/contents2.html
M.A.C: http://www.strafe.com/mac/index.shtml