Thank you very much for great answers!

Indeed, SmartQ 5 seems not to be a suitable device for me, since running Skype is the single most important thing to do with one of these devices. I only hope Skype video call is made possible on N8x0 in the future...

Please correct me if I'm wrong. The reason for not wanting N800 instead of N810 is the size. I hope to carry the device everywhere, from bed to bus. Pocketability/portability is really important. (In this regard, I hoped to have SmartQ 5 since it's much lighter than Nokia ones.) Also the GPS thing will be valuable from time to time, and carrying extra GPS module is somehow cumbersome, and it's not likely to be with me every moment. I'm forgetful... On top of that, N800 seems to be found nowhere these days... The extra keyboard might be useful sometimes.