The HD mod for UI improvements, bug fixes and the ability to play in any resolution; and Horn of the Abyss for a mod that feels like it could be an official expansion pack and adds a lot of neat stuff including a new faction.

I concur.

One more thing to recommend is the SOD SP plugin for HD mod. It makes the game with HD mod even awesomererererer. ;)

Does it work with The Restoration of Erathia and Armageddon's Blade campaigns? Also just for curiosity - does did mod has numerical value for creature numbers? Does HD mod has it? I checked HD mod some time ago, but don't remember if it had those.

The creature stack number not shown numerically always bothered me. It's cool for atmosphere like pretending the scouts could not count and gave you those expressions, but it would be nice to have and option in a game to show the numerical value of the enemy's approximately [for instance "Swarm (250-499)"].