Ack for the recommendation of Nokia 6150. It has the same charger as 770, so there is one object less to carry around. But phone recommendations are very much operator and plan specific. It's very hard to give a "universally best" phone. But for general n770 friendly phone, look out for the following features(in decreasing order of imporatnce):

• Supports the best speed your operator has
• has bluetooth
• how good it looks and feels in your hand
• price
• does it use same Nokia charger as 770
• does it use rs-mmc cards like 770?

Nokia 6150 has all of those but rs-mmc. My operator supports HSPDA, but with very limited coverage, so it doesn't really matter it isn't supported by 6150.