iPhone ads for the first iPhone win by a landslide in terms of elegance and shock value, starting with what is in my opinion one of the greatest ads ever, the Hello ad, it manages to be discrete, familiar, and so effective and making you shocked, this is in a time where phones with millions of buttons and stylus' were the big fancy phones and seeing an ad so dramatic for something like this just changes everything, then you get to the original ads that show off the features and it's like, at a time that smartphones with app stores and touch screens didn't exist, this was years ahead and absolutely shockingly amazing.
In terms of most effective, I honestly think that the "There's an app for that" ads created the best ads, here's again something completely un heard of before that is a huge revolution and a catch phrase that is so catchy and people still use, marketing genius.
I don't recall much of the ads for the 3gs, i thought they still used the there's an app for that stuff.
With the iPhone 4 ads I loved how they started with the compelling facetime ads but it ended and was replaced by the cocky if you don't have an iphone ads which i really just hate, It doesn't have that edge and shock that the first few iPhone models had and that the iPads had, so I'm hoping that the iPhone 5 will redefine the ads and bring it back to what they were before, something like a new "Hello" commercial would make me way too happy!