I don't really see the point of this topic but if you want an N900 than you should still have reason to keep your N810. Mer(hopefully) will keep the N810 alive for a while longer and remember. The N810 has a bigger screen than the N900 and I really don't see the point in selling it unless your desperate for cash.

Sell it if you want but you won't get a ton of money for it and it still has some advantages over the N900. But based on how little info was given I don't think this is a really serious topic.