There are loads of reasons to go to Iceland, from sleeping in a bubble and watching the Northern Lights to eating rotten shark meat. If Reykjavik doesn't register on your bucket list that doesn't mean you can't go. Icelandair will let you take a free layover in Iceland on your way to Europe, and you can find good deals right now.
Flying from the US to London, you'll find cheap winter tickets with a free layover in Iceland where you could drive the ring road or lounge in the Blue Lagoon.
Even from the West Coast, you can find cheap fares, like the below trip in January from Seattle for $335. Other deals include flying from Toronto for $357 (USD), New York for $369, Boston for $383, Orlando for $416, Edmonton for $434, Washington DC for $445, Chicago for $469, and Denver for $478.