spindown: Last update: June 15, 2013

I was pretty confused by all the existing patches and mods for Fallout 1, so I did a little research to find out what the essentials patches and mods are and where to obtain the latest versions. Some of this information was already scattered around this thread. Since I wanted to save you some work and since the OP is a little outdated, I'm going to collect the information here.

The best sources of information are No Mutants Allowed (NMA) and the Vault-Tec Labs Wiki. The state-of-the-art patches for Fallout 1 were made by TeamX, a Russian collaboration. Some of the information and download pages are only available in Russian, but that's not really a problem.

Now, first of all, the GOG version of Fallout 1 is the censored UK version. Most notably, children have been removed from the game. Furthermore, some drug references have been excised to make the game more family-friendly. That's obviously unacceptable, but luckily both of these issues are fixed by the semi-official patch by TeamX (see below).

There is also an unofficial patch by TeamX which aims to remove any remaining bugs in Fallout left in the latest official version. It does not make any gameplay changes. Save games made using the unofficial patch may be incompatible with previous versions of the game.

The latest bug fixes can be found below. I would consider the semi-official patch, the unofficial patch and the high-resolution mod essential for any player.

Semi-official patch (latest version v1.2.1 RC)
-------------------------
Semi-official patch v1.2.1 (fallup-1.2.1-EN-RC.rar)
Semi-official patch v1.2

The semi-official patch includes all official patches and applies them to all English-language versions of the game. It is required for further patching even if the game states that it is already patched to v1.2. Note that there used to be a separate patch to restore children to the game. That patch is now obsolete because it is included in the latest version of the semi-official patch.

Unofficial patch by TeamX (latest version v1.3.5)
---------------------
Unofficial patch v1.3.5

Note: The unofficial patch v1.3.5 requires the semi-official patch v1.2.1, so you need to install that first. So if you're purely interested in bug fixes, install the GOG version, then update to v1.2.1, then to v1.3.5. The main menu will still state v1.2 after you have installed the unofficial patch.

High-Resolution Patch (latest version v4.0.2)
-------------------------------
Fallout 1 High-Resolution Patch v4.0.2

The high-resolution patch allows you to run the game at higher resolutions than originally possible. It also includes the "sfall" patch to fix some black screen issues, so it's worth installing even if you don't intend to play at increased screen resolutions.

The three patches above are essential, and I highly recommend every player to install them.

In addition to these patches, which only remove bugs, there are also some mods that introduce changes to the gameplay. Whether or not to install them is a matter of taste. If you want the vanilla Fallout experience, or if you are playing Fallout for the first time, you should probably only install the three patches above.

NPC Mod (latest version v3.5)
-------------
NPC mod by TeamX (f1npcmod.rar)

This mod was made by TeamX, the same guys who made the above-mentioned patches. The mod introduces leveling-up for the various NPCs you can recruit in the game. You can also change armor and combat tactics for the NPCs and order them to move out of the way when they block a doorway. This mod requires the unoffical patch, so install the semi-official patch and the unofficial patch first.

End Game Mod
---------------------
End game mod v002 (SPOILERS!)

This mod allows you to continue the game after the end of the storyline.

Fallout Update Mod (latest version v1.2.5)
---------------------------
Fallout Update Mod (f1upmod125eng.rar)

This confusingly named mod intends to restore some elements that were removed from the final release of the game. It adds 4 new quests and 27 characters to the game. Note that it is *only* compatible with version 1.1 of Fallout. Therefore, it will not work with the GOG version of the game, which is patched to v1.2.

Fallout Restoration Mod (latest version v1.0b1)
---------------------------------
Fallout Restoration Mod (FO1RPv10b1.7z, requires the unofficial patch v1.3.5)

This mod is work in progress and a successor to the Fallout Update Mod. It builds on the latest unofficial patch. It is compatible with the NPC mod which should be installed before the restoration mod.

Fallout Revisited Mod
------------------------------
Fallout Revisited

Another mod with a misleading name, this one changes weapon damage and armor stats with the intention of making them more realistic. This is the successor to the Fatal Damage Mod, which is now obsolete.

FIXT Mod Compilation (latest version: Alpha 4.1)
------------------------------
Fallout FIXT mod compilation

This is a compilation that bundles together various patches and mods. It conveniently applies all kinds of patches and mods, but may install some mods that you don't actually want. Read the description at the link below to see what FIXT actually includes.

Other Mods
----------------
For any other mods like trainers etc., see FIXT mod compilation description.

Obsolete Patches and Mods
---------------------------------------

The following patches and mods are outdated and shouldn't be used anymore:

- Official v1.1 Patch (included in the semi-official patch v1.2.1)
- Sfall mod (There never really was a Fallout 1 version of sfall. It was mostly a fix for black screen issues that is now better addressed using the resolution patch)
- Fallout Children Patch (included in semi-official patch v1.2.1)
- Fallout Patch v1.3 beta created by Avega (superseded by the TeamX unofficial 1.3 patch)
- Fatal Damage Mod (superseded by the Fallout Revisited Mod)
- Dialog fixes by Nimrod (some fixes for grammar and typos in the dialogue; there doesn't seem to be any version that's compatible with the latest patches)

If I made any mistakes, please let me know and I'll update this post.

vsalcedo32: None of these mods have worked for windows 7 and still screws with my resolution. Starts the game and says it want 1900 by whatever the other number is. I'm just not very smart when it comes to computers I would like a mod that automatically does it all for you.

Nirth: How stable is this FIXT multi-mod? It seems to incorporate a lot of stuff with just one mod, but stability might suffer because of that.

BeastBad1368: Does anyone have a backup file for this mod because it said on the sit that "The file you selected does not exist."?

Kank: That's an old version. Try the latest here:
http://www.nma-fallout.com/forum/dload.php?action=file&file_id=1441

vsalcedo32: None of these mods have worked for windows 7 and still screws with my resolution. Starts the game and says it want 1900 by whatever the other number is. I'm just not very smart when it comes to computers I would like a mod that automatically does it all for you.

PannicAtack: This has probably been answered, but is there a mod/bugfix that restores the good ending for the Followers of the Apocalypse by making the relevant quest completable?

Sduibek: Hey all,

Like someone said above, if you're going to use my mod (FIXT), make sure you install the alpha 6.4 patch, as it fixes crashes.

Sduibek: .
FIXT should make this error go away -- this is because it includes the high-res patch, but also has some other 3rd-party programs that can be run to get rid of the "scrambled colors" issue, even if you're not running in high colors or high-res.

Also you'll want to grab the newest version of f1_res, it's now 4.1.7 and you can always find the newest version here: http://falloutmods.wikia.com/wiki/Fallout1_Resolution_Patch

Sduibek: .
Is the quest needed the Spy quest?

Cheers,
--Sduibek