So after almost 500 hours in this game and prob another 500 hours that will come in the second one I feel like I can finally review it.
M&B: Warband is unique in so many ways, you truely just start with you, few gold, some weapons and thats it. From there you have to build you way to take over the world which is not as easy as it sounds.
Story there isnt much of as said above is pretty much it, it lets you create and do what you want in the game world only story there is, is take over the world kill everyone else. How you choose to do so is upto you tho.
There are small "quests" within the game that will give you exp to level yourself up aswell as your army with skills that will benefit either you, your army or your entire kingdom.
This game is not a game you buy due to amazing graphics or amazing sound, it is a game you buy for it´s dept and for the fun of leading grand armies to major battles and seige battles.
I can honestly say after my 460 hours I havnt won the game not even once, always made a mistake or didnt capture enough castles or even worse did get to many. It is a game that has a deep connection with the middle and dark ages.
Marry your way to fame, kill your way, capture or just to mess with it all, conquer the world.
Mount & Blade will live for a long long time and there is amazing mods all the time that gets added to make the game even better the two main things you should add in my eyes to get a even more amazing experience is -
Floris Mod Pack - http://www.moddb.com/mods/floris-mod-pack
Warband battle size - http://www.nexusmods.com/mbwarband/mods/1761/
Those two mods makes it possible to have battles upto 600 units on both sides and it looks amazing, seeing your proud army just clash and kill 100´s of other units, aswell as adding even more dept to the politics and basic gameplay of the game.
All in all M&B: Warband is one of those games that truely proves that a game dosn´t have to be about graphics/sounds or any flashy flashy stuff, to make a truely unqiue and amazing game that will keep you trapped for years.
So if you are looking for a game that will ruin take your soul for a few 100 of hours grab this game for sure, it is one of my favorits and it is really one of those games that is 100% what YOU deside and make of it.