Thought I would make a thread detailing some of the stuff you should be stockpiling for the expansion. Maybe this is based on beta testing, maybe it's just common sense, NDA's might prohibit me from being more specific so take this with a pinch of salt
1) Platinum - real no brainer
2) Planarite - still the basic planar currency
3) Inscribed Sourcestone - Unlikely to be the epic currency of choice in SL, but you can convert it to Planarite so stockpile it
4) Favor - if you're into PvP anyway
5) Master Craftsman Marks - some rumours they're used to buy SL recipes, take with a pinch of salt.
6) Artisans Marks - same as above.
7) Lucky Coins - same as above, but for items not recipes. Again, pinch of salt.
Crafting materials are likely to be useless, replaced with a new tier. Getting good gear is only a method of leveling faster or seeing current content.
Can't think of anything else, let me know if you guys can divulge anything without breaking the NDA or if I have inadvertently broken it