Posted November 18, 2012
![avatar](/upload/avatars/2012/05/73e3640b59f04f198734cf312fe27ecf01b581e8_t.jpg)
6,7 and 8 are obviously game changers to the series judging from the screenshots.
![avatar](/upload/avatars/2012/11/efb437e45527442efbf418fcebf69ea79771f010_t.jpg)
Ultima 2 -- I never got into this enough that I feel I can comment on it. It takes place on Earth, for some reason, and you have a time-travel mechanic.
Ultima 3--there is now a party system
Ultima 4--The real game-changer. The Avatar makes his first appearance, there's finally a conversation system, and the world of Britannia is introduced. This is the natural place to start, if you're looking to get into the series (I only played the first three because I'm kind of neurotic about playing series in order).
Beyond that, mrcrispy83's link looks pretty thorough.
Post edited November 18, 2012 by Elmofongo