User Interface (QI Inventory) - http://www.skyrimnexus.com/downloads/file.php?id=667 [Requires Update 1]
Tired of the consolised scroll menus? Fear no longer, as this beautiful mod completely revamps the inventory menu, allowing mouse selection and wheel scrolling. And if things couldn't get better, you can even sort the items from lowest to highest in terms of Value, Weight and Damage etc.
Image: http://static.skyrimnexus.com/downloads/images/667-2-1321715262.jpg
Please note that this screenshot does not reflect the current version and the font is not affected by the mod. Default font will be used if you install this mod without any font editing
Smithing (More Craftables) - http://www.skyrimnexus.com/downloads/file.php?id=799
If you feel that Smithing is more grinding than rewarding (I'm looking at you iron daggers), then this mod is for you. This mod allows you to make tonnes more items via smithing, which makes the skill feel challenging and rewarding. To add to immersion, the required items to make an object is relevant to the object itself, and I feel that this is definitely better than grinding the same iron dagger over and over again.
Image: http://static.skyrimnexus.com/downloads/images/799-1-1321825128.jpg
Horsies (Faster Horses) - http://www.skyrimnexus.com/downloads/file.php?id=934
Let's face it. For 1000 Septims, horses are practically a rip off. They lose stamina almost instantly and they run slower than a cabbage plant. With this mod, the horse speed is buffed by 1.5x which makes the boost realistic and useful at the same time.
Texture/Graphics (FXAA Post Process Injector) - http://www.skyrimnexus.com/downloads/file.php?id=131
Although Skyrim is one of the best singleplayer RPG's out there, I'm sure almost all of you have noticed the substandard textures and graphics in certain locations or just generally. Even if you are running on low/medium settings, this mod can make your Skyrim look more sharp and defined, which is why I would recommend this. There are also many settings you can play around with, if the default presets are not what you desire.
Image: http://static.skyrimnexus.com/downloads/images/131-1-1321216439.png
(killing children mod removed, google it)