I for one enjoy the concept behind the DLCs that give you houses, my only complaint is that I wish a bit more story was put into them. I mean, for the Fighter's Stronghold and Thieve's Den DLCs, it's just a matter of clearing out some baddies and then buying a few upgrades to make it a proper house and then some. Wizard's Tower and Vile Lair didn't even require you to fight anything.
I also don't really like the more minimal DLC packs. Horse Armor is barely a thought in my mind of course, but I've only ever found 2 Spell Tomes in the time I've had that DLC, and while the Orrery looks cool, it doesn't do all that much for me.
That said, I highly enjoyed playing through the Mehrunes' Razor quest, giant dungeon full of cool items and large, interesting areas? That's DLC done right, I hope we can see DLC of its quality for Skyrim.