Dude, it's the elder scrolls. It's THE fantasy epic. It's amazing for one simple reason. It's whoever YOU want to be in a world they create. In a realistic leveling up manner, where the skills you use are the skills you master, so for instance, if you want to grab a sword, instead of assigning 20 skillpoints to the sword skill, you start using, and by practice you earn skill with that sword, so later in the game you will swing that sword like a boss, and there's this system of reward, where to master a skill, you must use it constantly, and every time there's this little music, that tells you you've gained more points for that skill, you feel awesome, like in real life, when you realize, that thing you practiced over and over and over again, had a great impact on your life. Also the openess and the quests and the gazzilion NPCs with miscelanous quests that can keep you going for days. The world is also put in a very realistic manner where you feel the immersiveness from the minute you step out of that prison, morrowind more than oblivion, but Skyrim goes back to that (based on the concept art). The first person does it's part as well because you feel as if you were the dude doin' the killin. So yeah, that and other factors make skyrim great, because that's what made Morrowind and Oblivion great, and if it improoves on that, it will be the greatest game EVARRRR!!!!!!
Also dragons dude, dragons.