LEGO!!!!!! Everything else came a distant second. MAD magazine for sure, loved reading those back in the day. And the original Nintendo (NES) with Super Mario Bros and Duck Hunt and ROB the Robot for Gyromite.
Still have most of those things to this day. No pristine boxes or anything, but most of the toys and definitely all the Lego pieces. Even managed to rebuild them all a few years ago using instructions found online for some of the missing ones. Last few years I've done more of an 80's theme at car shows than strictly just Back to the Future. I put a few of those toys out for that.