The white iphone 4.
I started with the 3rd gen, and got the Black iphone 4 on launch day by making a reservation. Remember, the TV commercials - “there is an app for that” and “this changes everything”. I adored my black iphone 4, until the next spring when the white came out. I remember walking into an apple store, seeing the white version, and I immediately had to have it. I sold my black one, paid full price for the white phone, and that became my baby until the iPhone 6. The 6 has been my baby until Nov 3rd when I get a new baby 🙂
I still have my old white iphone 4 on display in my lounge, alongside my old Nokia 3210 - another classic, my 1980’s Nintendo, and and my old retired iPad 2. I don’t think the iPhone 6 is quite worthy to go alongside the above, but I get the feeling that the iPhone X will one day take it’s place alongside those legends