You mentioning Half Life there reminded me of one of my all time favourite Half Life Mods :

They Hunger, it was origionally a 3 part story as it was being released, you can get it as a single download now though.

For me, it's the Better than Wolves mod for Minecraft. Expanding the game in so many ways and even making the Nether useful. This mod alone was enough to bring me back to the game. Plus, the author is quite funny.

Haven't played many, but I'd say A Dance With Rogues. Holy pancakes.

I should check out Nehrim sometime...

I actually thought for a couple of hours about it, and arrived at the conclusion that it's totally impossible for me to answer the question. I've played so many totally different mods for so many totally different games that there simply isn't any yardstick that could be used to measure and compare all of them.

As an example: Some of the great mods for Civ4 include:

- "A new Dawn", an aggregate mod that adds tons and tons of features to an already very complex base game
- "Fall from Heaven", basically a whole new game
- BUG mod, a UI mod that is much smaller in scope than each of the two above, but that's incredibly useful. I immediately miss it when I'm playing a mod that doesn't have it integrated
- Better BtS AI, a mod that adds no content at all, but considerably improves the AI.

How could one determine which of these mods is the "best" one? A fair comparison simply isn't impossible, they are simply too different.

And these are only mods for _one_ game. Now let's just add one other game, say, Morrowind. This will give us at least a dozen of _additional_ categories: new quests, new items, new creatures, essential bugfixes, useful tweaks, texture and mesh improvements, new gameplay mechanics, player homes, total conversions, new sounds, new landmasses ... and this list isn't even exhaustive.

So, at least for me, asking for the "best mod" is similar to asking questions like "Who's better - Beethoven, Philip K. Dick, or Salvador Dali?". I can't answer that one either. :)

JA2 1.13 for Jagged Alliance 2. This mod adds so much extra tactical options to the vanilla game.

STALKER Complete 2009 for STALKER Shadow of Chernobyl. Got it for the high-res textures. I don't really know what else it adds to the vanilla game since I've never played the game in its unmodded form. It sure looks spiffy with the new textures though :)

I don't know if it's the "best" one, but The Nameless Mod for Deus Ex was extremely well made and enjoyable.

As far as total conversions are concerned, I think that Third Age for Medieval 2 TW takes the cake.

As for other kinds of mods, the Stalker Complete mods and Morrowind's GCD mod are among my must-have mods.

The original Day of Defeat mod back when all great HL mods were free with HL purchase. Now they sell every old mod separately.

Had a blast playing Day of Defeat on my old machine. Sure I wasn't that good, but I had my moments.

That's subjective though. I love the Elder Scrolls series, but I don't find the lack of XP-based progression a good thing. It allows players to max out every skill and attribute without making a choice between different abilities or sacrificing anything, really. I prefer the approach used in Fallout 3 and New Vegas myself.

Zombie Panic: Source

Teaches you a lot of evasion tactics for shooters playing a zombie constantly.

Well the whole point of Elder Scrolls games is freedom. No one is forcing you to max everything, as well as no one is forcing you to steal everything you see and to kill everyone you see. That's all up to the player and it wouldn't make much sence for this kind of game to include a system that restricts the player.

Fair enough, and another great virtue of the ES games is that they are extensively moddable, making it possible for each player to fit to game to their own unique needs. Players who prefer freedom and those who would rather see character progression restricted in some ways can both enjoy these games. :)

Thanks. :)