Gotta think way back to childhood...
Well, toss-up between the "car" Voltron (Christmas '84 or '85?), and Sega Genesis (slightly pre-Christmas '91).
The Genesis, since sold, was, and remains my only other experience with owning a console aside from my treasured 2600. Nonetheless, the system left me with many good memories, and Sonic was just an unbelievable audio/visual experience for a console-deprived soul like me---quite an improvement in all aspects over playing SMB 2 at a friends place three years prior. And for some reason, a listen to "I Love Your Smile" rekindles all those fond memories.
The "car" Voltron was umm... VOLTRON!
Voltron=5up3r-/\/\3g4-u17r4-g3nu1n3-1337n355
Honorable mention: Awesome, h-e-a-v-y denim Bugle Boy jacket in '88 from The Broadway. First $100+ gift.
