Hmm, tricky. It' easy enough to think of things that would be useful - but the whole point is that anything available solely from the Gemstore should not be capable of giving an advantage to a player with more RL cash. Personally, I don't want to end up with a game where money talks. Given that, my two suggestions would both be for the much-ignored (apart from daily harvesting) home instance: furnishing / fluff items. There's a great need (in my view...) for at least some placeable basic furniture in the home. Beds, tables, chairs, etc.a large map/globe of Tyria. It could be updated as new Zones are added, and maybe even show which zones you've explored fully.