no game is really worth $100 especially when I live in the uk so will therefore have to pay £100

It will be rather hard to market a game and make momey for the n900 as we already have a large selection of games thanks to the great emu's out there, the best bet would be to make an mmorpg for the n900, pc any other pocket devices that doesn't need awesome controls as we only have a small keyboard, it could be made free for a month and then subscription or something... That way you could make your £100.

Having a game like eve online but but easier to play on the n900 would defo make some money as would a world of warcraft.