black iPhone 3G
white iPhone 3GS
black iPhone 4
white iPhone 4S
white iPhone 5
white/silver iPhone 5s (not sure why Apple is now using lowercase letters for the 's' and 'c' phones)
I used to buy and sell jailbroken iPhone (first gen) on college then do minor repairs plus add unlimited data to accounts in grad school, so I am well over 28 over the years.
Well I've owned every single generation and used more than one at a time. I don't know how you count ownership, but I buy a lot of iPhones. I think I bought like 12 last year...