gammaleak: Thanks everyone for the suggestions! I'll give U4 a try and see how it goes. I'm a neurotic completionist, so if I like it, I'll probably start from Ultima I.
Don't worry, I'm not crazy enough to try Akalabeth first. ;^)
I have the same problem you have, I can't stand the thought of starting a series from the second game (let alone fourth game!).
That said, the Ultima games are very different apart, both in story, world, approach of the main character, objectives, and of course, technology (graphics, sound and gameplay). So if it makes some difference for you to play the most accessible installments in the series, I'd definitely discard Ultima 1-3, starting with Ultima IV (perhaps using the Xu4 remake
http://xu4.sourceforge.net/ along with the graphics update patch) and, if you still don't like it, start right out with Ultima 6, which is a prelude to the best RPG ever, Ultima 7.
Here's what you'll miss from a simplistic point of view:
Akalabeth: Richard Garriott didn't even know he was going to create on of the major franchises of CRPGs, so he just made a dungeon crawler with no places to visit or people to talk to.
Ultima 1: very early Ultima history, it pretty much recreates the world, you feel the world has no history at all, very basic.
Ultima 2: it includes a plot in the real world (yeah, Earth and the Solar System) and expands the villain from Ultima 1.
Ultima 3: although expanding the history, the early Sosaria geography is completely disregarded and recreated again. People explain it saying Sosaria was composed of 4 continents and 3 of them were destroyed by a cataclysm, but the remaining continent is completely different, bringing many inconsistencies. The gameplay itself looks like Ultima 4.
Ultima 4: fans everywhere will throw bricks at me, but this is a complete reboot of the series. Both the earlier geography of Sosaria and the basics of the story are disregarded, bringing for the first time the continent of Britannia and the focus on the 8 virtues that will mark the rest of the series. This is very inconsistent with earlier games, but much better also, and more mature.
Ultima 5: expands the story and world of Ultima 4 consistently.
Ultima 6: expands the story and world consistently with revamped graphics and much more accessible gameplay!
Ultima 7: expands the story and world consistently with better graphics. Best game of its time and best RPG yet.
Ultima 8: regards earlier story but takes the game to a different world, because that's what Richard Garriott does since he was a teenager. There's no Lord British, so you know the guy was on crack.
Ultima 9: lacklustre attempt to return the story to classic Britannia, and that's about the only thing really good in this game.
So above you see why I pretty much don't bother playing the first trilogy in favor of the second. It doesn't make much of a difference for the story, and the games are much less accessible. So, yeah, as a collector and huge fan, I own all of them, but actually playing the first ones is not that sexy.