MrGarry2u

Base Game Skyrim:
You either have it or want it really. One of 'those games'. The game's newest update adds a LEGENDARY difficulty and an ability to extend your skills past 100. Perfect for those bitches who got their enchantment to 100 so they can 1 hit kill everything.

Tool Creation Kit
Good for minor tweaks or big old dirty scars on the land of Skyrim, if you want to learn how to use it instead of just using other people's mods and plugins.

DLC Dawnguard:
A nice add on that adds to the experience of being a Vampire, Werewolf or even remaining human-ish and slaying BOTH abominations. Vampirism is brought up to Werewolf level as they now both have a second form and their own perk tree. If you remain untainted you still get access to Crossbows. Also this add on puts a lady in the Ragged Flaggon who can change your face using in-game means rather than console cheats... costs 1000 Gold.

DLC Hearthfire:
Lets you build a house in holds where you are in with the Jarl, the house seems to be the same where ever you build it, but it has enough choices along the way for each wing to make it feel personal. Also adds the ability to adopt kids. Kids who are wondering around each hold moaning about their dead parents or abusive uncle. I won't be adopting a Bethesda child until they learn to give less of the lip. Little shits.

DLC Dragonborn:
The story gradually adds an ability to fly dragons, increase the power of some of your standard shouts, and at the end grants the ability to redistribute your stats and perks. As for the island it takes place on, there are lots of Tombs, caves and all the usuall free roaming things to be done. New shouts to be found. Good if you want to make your Dragonborn the undisputed kicker of many asses.