Skyrim Redone and Deadly Dragons are two of the biggest mods on the nexus right now. Skyrim Redone is basically a major Skyrim overall that also includes changes to the skill system. (You will have to start a new game over.) Deadly Dragons includes dragon difficulty customization that allows you to make the dragons harder and realistic. If you want to get hardcore with realism then get Imp's more complex needs and Frostfall - Hypothermia Camping Survival. I also recommend getting DYNAVISION - Dynamic Depth of Field, IMAGINATOR - Visual Control Device for Skyrim, Project Reality - Climates Of Tamriel - Weather - Lighting, RCRN v35 HDR - Your AllinOne Lighting and Immersion, Texture Pack Combiner if you want a more immersive and better graphical experience, if your computer can take it. Go sign up at http://www.razerzone.com/gamebooster/signup so you can get an invite to the Razer game booster beta so you can increase your game FPS. If you haven't already done so go browse the Skyrim Nexus for mods. Currently of as this post there are 23,120 different mods available.