Something I've been wondering lately:

What would you say is the definitive version of each Ultima game from 1-6 (and we can include Akalabeth as well)?

There are a couple rules that I have about what qualifies:
* It must be an *official* release of the game. Fan ports and remakes do not count, nor do engine re-implementations (like Exult), or patched versions (Ultima 1-5 with the fan upgrade patches). The versions found on GOG count as being official for this purpose.
* Ports that differ drastically from the original, to the point where they arguably aren't even the same game, don't count, as I couldn't really call such versions *definitive*. So, for example, we wouldn't count the NES versions of Ultima 4 and 5 here. (Then again, I don't think *anyone* would call NES Ultima 5 definitive, as it's kuso-level bad.)

In any case, it only makes sense to go through Ultima 6 here, as Ultima 7 really has only one official version (as I've excluded Exult from the rules. and SNES Ultima 7 looks like it differs too drastically from the DOS version), and the same can be said of later games.

As someone who's beaten all the Ultima games, I will reply.
Akalabeth (DOS version with music)
Ultima 1 (Japanese FM-Towns version of Ultima Trilogy, comes in English)
Ultima 2 (DOS version with Voyager Dragon's CGA Composite patch. If you speak Japanese, FM-Towns version of Ultima Trilogy--the U2 ending is in Japanese, rest can be set to English)
Ultima 3 (Lairware Mac version, can be run on Mac emulator for Windows)
Ultima 4 (xu4 using the Japanese PC98 tileset)
Ultima 5 (DOS version because you can import character from Ultima 4/xu4)
Ultima 6 (Nuvie with FM-Towns Ultima 6 Full Speech installed in config file)
Runes of Virtue 1 (Gameboy version, only version)
Runes of Virtue 2 (SNES port)
Savage Empire (Dos version)
Martian Dreams (Dos version)
Ultima Underworld 1 (Dos version)
Ultima 7 Part 1 and Forge of Virtue (Dos version)
Ultima Underworld 2 (Dos version)
Ultima 7 Part 2 and Silver Seed (Dos version)
Ultima 8 (Dos version)
Ultima 9 (Windows version with fan patch that prevents runes from getting stuck in sky after shrine cleansing)

Two issues with this:
* It's not an official version (some of the other ones you mention aren't official versions as well, or you are recommending unofficial patches)
* When I tried it, it seemed the damage amounts from enemy attacks were oddly low in comparison to other versions (not counting NES). Increasing the difficulty doesn't help, but rather makes your attacks hit less often, which is one of the worst way to handle a difficulty setting. Also, being faithful to the original mechanics, or at least what the mechanics were intended to be, is very important to me. (The lack of faithful mechanics was also an issue with Exult last time I looked at it; the natural regeneration of HP and MP did not match the way they did in official Ultima 7.)

Fair enough, but the ultimate quality of the games is lesser if you go only official port route. Say if you play FM Towns Ultima 6 without Nuvie, you'll get full speech but no choice to import characters from U5. If you play official Dos Ultima 6, you get the option to import U5 Avatar but no full speech.

At this point which version is "best" becomes subjective in regards to which features that individual person prefers. While my list incorporated fan stuff, it was only to combine the best aspects of various official versions.

How would one get this PC-98 tileset anyhow?
Also how do Pentagram and Exult stack up to the DOS versions

Hmm, interesting. Question for you, why do you prefer the DOS version of Ultima 7 over Exult? I really enjoy playing U7 using Exult with Marzo's mods.

D'oh! My bad, I now see the original topic question. Gotcha!

That's fair but since we're seeing this now we're kinda curious
On the original topic though ...isn't the entire FM-Towns original trilogy available in English along with the FM Towns version of VI which has voice acting? You can get that with Nuvie too iirc but since you'd rather not... A lot of people also enjoy the Master System version of Ultima 4 and hell even the NES versions of 3 and 4 have their fan. Whether or not they're worth playing over the DOS versions? IDK

I'm actually familiar with these versions, particularly the versions of 4. For 3 I prefer the DOS version, as the NES version has scaling enemies (so at higher levels the overworld becomes more dangerous, to the point where it's best not to level up past level 2 until you're ready for the endgame, except for one character raised to level 5 for the sole purpose of getting a ship to spawn (and then dropped from the party)), and druids don't get the faster MP regen that they do in the DOS and other computer versions.

Ultima 4 is interesting in that there are two console versions, and they're *different*:

* The NES version is essentially a complete re-imagining of the game. Many things are streamlined, combat has been re-done (in particular, it's not nearly as RNG dependent), you can equip both a melee weapon and a bow at the same time (the bow is used when not in melee range, while the melee weapon is used if you're in melee), and the game actually tells you how much damage your attacks do. On the other hand, there are some negatives, like fewer NPCs (especially if you're not playing the Japanese version), no nice dialog system (it's more like a JRPG where everyone has one thing to say), and many of the dungeon rooms were replaced with copies of other rooms. Also, for whatever reason, money is significantly harder to get, and the Key (you only ever need to buy 1 on NES) costs 2000. One interesting difference is that you have to go through the Abyss alone. Because of the differences, this game wouldn't replace the DOS version, but it is definitely worth playing.

* The SMS version, on the other hand, is more faithful. Conversation is done by selecting keywords, combat works similarly to the DOS version (except for the ability to attack in any direction, though unlike on NES walls will block your attacks), and the game is otherwise mostly faithful to the original. The only negative, aside from the occasional room puzzle not accounting for diagonal attacks from the player, is that, for whatever reason, there's no first-person dungeons. For whatever reason. dungeon hallways are overhead view, though at least all the hallway traps are retained (unlike on NES, where the first person view is present, but not the hallway traps). This version *can* replace the DOS versions, and for me it's actually my preferred version of the game (not counting the NES version).

By the way, did you know that the Japanese MSX version got *two* Ultima 3 releases? One, released on a cartridge, is a port of the Famicom (NES) version, while the other one is a port of some Japanese computer version that's more true to the original.

I have the PC-98 tileset cobbled together from material I found online years ago, but admittedly this patch I basically made myself isn't widespread. I myself might not remember how to share it if I don't remember which files were altered.

Also Ultima 2 FM Towns' ending is only in Japanese, even if you play the English port.

The Sega Master System version of Ultima IV is surprisingly excellent. The full game is there (except dungeons are 2d, like in Ultima VI), and the way you unlock speech topics means you can't cheat the game by going straight to an NPC and saying the correct keyword.

However, my vote for that particular game goes to the cartridge version of Ultima IV remastered on the C64 (emulated in Vice).

The intro is the best looking out of any version, and the game flows perfectly due to the cartridge format.

http://magervalp.github.io/2015/03/30/u4-remastered.html

Quite late to this thread (which I stumbled onto by accident) but just a small note to say thanks to sidv88, for those ultra-useful posts and insights. I may not be a huge Ultima fan (seem to be one of the few that thought U7 is one of the most overrated games of all time), but I do have a lot of fond memories of U3 and U4 from my early youth. Every now and then I'll get nostalgic to try one of the versions I never played, thus running into this thread (for Ultima 2 :) ). Anyway again thank you to sidv88!