I will also not update my iPhone much anymore, though to be honest I think 4.0 is quite buggy in many ways. But I want to jump ship to T-Mobile ASAP so I can actually make calls on my Phone. I wish they'd hurry up with the jailbreak. I'd be willing to pay to have my 3GS with 4.0 jail broken and unlocked if I knew it would work, thats how badly I want to get off of AT&T.
I think next time I buy an iPhone, which may be next year, I will probably just buy from a Canadian Apple store (got family there) and get it factory unlocked and save myself all the headaches and hassles (though granted, It'll probably cost me $500-$600, but when you consider $199 + $325 cancellation fee + 1 month of useless AT&T service, that just about breaks even anyway).