Maple Tree - I'm taking a slightly different angle here. We had a house in NJ that had a big maple tree in the middle of the backyard. At some point, early on, my dad decided to tap the tree so we could have fresh maple syrup. While it was great to be able to make our own, it also gave me a lot of perspective on how much it actually takes to make a meaningful serving of syrup (after boiling it down), thus also making me understand from an early age why the real stuff costs so much.
Anything maple bacon - I've used this combo in cakes and even candies where I candied bacon and covered it in tempered chocolate. I then finished it with crystalized maple candy shards.
The smell of maple - I wish more air freshener and candle companies would recognize this as a powerful fall smell. I would take this any day, wafting through the air, over pumpkin spice.