I have to vote for the A500. It was the cheapest of all Amiga models, so it really brought Amiga to the masses.
Agreed. The A500 is the winner by a mile if the criterion is contemporary price/performance ratio. Never again would the the Amiga have such a crushing advantage over the competition as in 1987. The 2000 had a nice big expansion case but was very expensive relative to the 500 (more than double the price in Europe).