Best mod?

Finally have time to play M2:TW again on my newly built PC. Last played just before Kingdoms was released and I feel very humbled by the current options.

Waiting now for my "new" Kingdoms delivery. From past experience I know the game is 1000% better with the right mod. So my question is, what mod would you all recommend for realism (biggest priority), then expanded units/factions, then eye candy. This all seamed so simple when I was playing and I don't want to waist time on "also ran" mods. Can't find a poll or a mod download count anywhere. Would definatly consider any minor mod as long as compatible with major mod. Thanks for your recommendations, your input is much appreciated.

PC:
Win7, Core i7 3770K, OCZ 256SSD, Corsair 16G@1866, MSI Z77A-GD80, EVGA GTX 670

I'd be interested if anyone for-see's a problem with my hardware too.

I've had an I7 for 2 years now, it's a great processor. Same amount of RAM, but i think mine is at 1600. My video card is a 570 if i remember correctly, so it doesn't perform as well as I'd like it with Shogun 2 max graphics.

For mods, I'd say Stainless Steel, Third Age Total War and probably single-player Broken Crescent.