Deffinately extra attomizers. cash posted in the PS forum he will be having some stainless colored atty's (verses the stock black) If color matching is a style issue, might want some when they are available also...now who makes a stainless colored tip

Oh, the new ones are also Low Bridge so worth trying just for that if what you have currently is a High Bridge type.
(I am all for different things being better for different people!)
Also either juice, or prefilled carts, or both.
If you have never tried different tip types, ie round, flat, whistle tips I'd suggest trying them out. I started with the rounds that came with my 510, and recently got 10 of the flat ones from Nhaler and we (wife and I) simply LOVE them.
Also while the 2 14500 batteries the ptotoge comes with will likely last a while as it only uses 1 at a time, it cant hurt to gave a few spares as if they go down, you are in trouble. Hellen A. Handbasket found a sweet deal and I am reposting her link here:
TrustFire Protected 14500 3.7V 900mAh Lithium Battery [TrustFire] - $2.68 : High Tech DealZ, Simplifying the LASER Hobby! she also got us a discount code for 10% off the allready great price: HELLENECF10 (Thanks again Hellen!)
Flavors, try some!
If you want to try mixing your own, then some diy supplies.
Also if you do try several flavors, a drop or 2 of 5o/50 pg/vg will help to clear out the old flavor rather well.
I am also awaiting 2 protoge's here, I hope you enjoy yours!