Bike fit and suspension for my size come first , get comfortable first and then modify the rest.
1. Lower pegs , taller seat , forward / up bar mounts etc.
2. suspenion set up for the woods ( some of todays bikes are not that bad stock )
3. large tank , handguards and other woods related add ons
4. the usual bling bling stuff that is a waste of money but nice to have comes next such as I am in the process of lacing up an 18 for the rear of my bike. Not really a have to have item but nice to have in the woods.