I was a huge Iron Maiden fan when I was in junior high (late 1980s--I'm old). I bought metal magazines and made a scrapbook of their articles and my door was covered with their pin-ups and I had posters all over my walls and wore tons of their square buttons (remember those?).
But, before that, I was a huge KISS fan. Some of the first albums I ever had were KISS records my mom bought me from thrift stores, parking lot sales, used book/record stores, etc. (Gene Simmons solo, Dressed To Kill, The Originals, Double Platinum, Destroyer). I still listen to their music regularly. I have a set of KISS Majik Market cups on my bookcase I see everyday. I don't listen to Maiden near as much as I did back in the day while I've since collected KISS albums I didn't have back then (Elder, Creatures, the other solo albums etc.) and love them (even Peter's solo albums). So, to me, KISS is an easy choice. They are a top 5 band (maybe #1) off all time for me.