Joining the tribe soon (Challenger Dark Horse), what are some must have addons?

I've always been a metric bike guy, just could never afford the Harley I would have wanted. Coming in to some unexpected money soon and I was looking at both the Ultra Glide and Challenger and it looks like the Challenger is just an all around better bike (stock). So now I'm getting on board the Indian train.

Wife just gave the go ahead on the Challenger, and was wondering what some of the must have addons are from you guys who have purchased one, or ones that you purchased that you now wish you wouldn't have? The wife's only requirements are the sissy bar package and floorboards for the passenger