I'm making this thread because I just had my most fun fight in Skyrim so far. If you have not fought Sigdis Gauldurson I recommend not reading further, because of spoilers.
This is a backup line in case someone just skips reading the first line, there are spoilers about Sigdis Gauldurson.
Third Backup line, spoilers about Sigdis Gauldurson, turn back if you do not know who this NPC is or continue at your own risk.
There, now I feel like I don't have to put this inside of a spoiler tag. On to the topic at hand, I was pleasantly surprised when I fought Sigdis Gauldurson, I entered the cold damp room and immediately noticed the two platforms and started to wonder "Just what are they for, there is nothing on them, almost like they were put there only for the benefit of players who use ranged attacks so they can have an advantage to work with in the boss fight." I went up the stairs and a loud boom was heard that shook the room, I was already used to this from fighting similar Draugr bosses so I did as I usually do and threw my alteration shield spell on myself and summoned my flame atronach.
And there he was, Sigdis Gauldurson, a powerful undead adversary with a mighty... bow ? Pwah, easy I thought charging forwards with my mace but to my surprise my mace hit nothing and all of a sudden I was standing there fighting the empty air while my flame atronach was shooting fireballs behind me and a sudden realization came upon me as I remembered the platforms in the middle of the room, and turning around only confirmed my guess of what had happened as an arrow flew straight at my face, or scrap that and make it "arrows", I was suddenly not fighting just one Sigdis Gauldurson but three!
"No biggie, I'll just heal myself and... what is that blue glow ? What is happening, where is my mana ?" *Gets shot with an arrow, starts to glow*, "oh..."
"Crap!" I duck into a corner and spend a mana potion, I use the mana I have to fill my health and as I finish healing and draw my weapon I see my flame atronach get killed "no matter, those are archers and I know where they are, I'll just charge at him, and take him down, 3... 2... 1... CHARGE!"
Sigdis Gauldurson: "FUS RO DAH!"
Suddenly I'm down in the water as two of the Sigdis Gauldursons loose a volley of arrows into my limp body. I gather myself up and make a mental note that there are only two but not three now, and my atronach couldn't have killed one of them if they all had the same health as a normal boss so they must go down easy.
However I myself only have half my health now and it's going down at a moderate rate, I decide not to duck for cover yet but to try and take one of them down, perhaps he really has very little health.
Sigdis Gauldurson: "FUS RO DAH!"
I'm blasted away again, this time however into cover from their arrows, I gather myself up making another mental note that they must all be able to use that dragon shout and I decide not to charge at them but to try and push them off the platforms myself. So I take a peek at them to discern their locations compared to my own and I run towards them but stop halfway preparing an unrelenting shout of my own, I notice one of them is glowing while the other is not and I make a snap decision to use my shout at the glowing one. The glowing one falls apart but before I can make my charge at the last one who I decide must be the real one and considerably tougher I notice my mana is down and my health is running low, so I hide...
There I am huddled down in a corner waiting for my mana and I notice I'm quite pumped, "this is relly fun!" I think to myself and here I had been expecting just yet another melee who would just charge at me not really making a dent in my health because of my crazy focus on melee defenses or a mage who would blast me in one hit with crazy spells making me have to resort to the fun old "atronach + constantly shield bash the enemy if he looks like he is going to cast a spell at me" tactic.
Really, I came to love this fight more and more as I went on and I learned more about it such as that the "real" Sigdis had pretty decent health so that the fight would last for a while and that he could use his teleport + make copies of himself trick to no end and having 3 enemies at the same time capable of throwing an unrelenting force dragonshout at you can be quite interesting. It is truly the most fun fight I have had so far in the game and this kind of versatile tactics is what I expected from dragons. Imagine if a dragon could make mirror images of itself, drain your mana, teleport around, forcepush you away and still have a ranged and a melee attack while still being physically tough.
But this thread is not supposed to be about dragons, it is supposed to be about Sigdis Gauldurson and the awesome fight he gives us. If you read through this then I hope you have fought him (else my spoiler lines were in wain

So share your thoughts. The only negative thing I have to say about Sigdis Gauldurson is that Sigdis is a girls name and a pretty girly one at that (a frilly name like calling a girl "Princess" or "Honey" or something like that), Sig means victory and dís pretty much means something along the lines of "beautiful goddess" and we translate "beauty queen" as "fegureardís" here (fegure = beauty, but dís doesn't quite mean queen but the meaning is there). So when I see his name I think of a Draugr with lipstick in a sparkly dress winning a beauty contest... not a badass ranger of death who has claimed many lives.
But enough of that, let's discuss some gameplay and awesome fighting!