How long does it take you to do the MQ, Civil War, Companions, Mages College, Thieves Guild, Dark Brotherhood, Bards College, Daedric artifacts, collect all dragon priest masks, Dawnguard, and Dragonborn?

Around 1000 hours.

It really depends on how you decide to play, but it took me around 300 hours in total.
EDIT: It took me 350 hours without Dragonborn

Fastest time I done it was 60 hours.
My only other time of doing everything except for 1 dragonpreist mask, took me 300 hours.

no joke on this, my first character racked up 975 hours after i have finished the dlc and everything else except the Dark Brotherhood.

60!? Wow. You're a skyrim-playing machine

I wanted to see how fast I could do it. So I made instakill gauntlets and I done it within 10 days.

depends on how you play..i like to take my time and explore run around cut wood, do mic quests, help people, discover locations..read and find books, cook, do alchemy.. that in itself is about 100 to 300 hours right there depending give or take. Not even counting the actual quests and questlines, factions

only time i've done all the content available was within 200 hours, minus dawnguard and dragonborn

add those on, anywhere from 240-300 hours

You can really bloat game time by not fast-traveling and doing misc quests too! My Nord Female Nightblade is at 982Hours right now, and that's without the College-Companions-Thieves Guild. I've done just about every single Misc Quest in the game though, including one instance of every available Bounty mission in each hold.

Alduin-Dragonborn-Dawnguard-DarkBrotherhood-CivilWar are all completed though.

Mages or Bards college?

Mages College. The Bard's crap is more shallow than the Bounty quests, so I wouldn't even dream of calling that a "Faction" or "Plotline".

I'm 220 hours in and haven't completed anything lol, I think we can all agree Skyrim represents pretty good value for money

it does indeed.

Skyrim represents a great value at triple the price. That's why I'm really really REALLY hoping for a surprises Fallout4 announce at E3, in the same vein, Bethesda's games aren't just a great Value on their own, they're a great value with the Hardware too. For how much time you get with them, it'd be like spending 600$ at the movies.

im playing an altmer mage and ive done all of that except daedric, MQ, civil, and masks. and im at 240. it seems like many people realistically play for about 300 hours on one Profile, obviously you could do it shorter if your diliberatley trying to beat the game fast. and then you could go for dungeons which is a whole different thing, also extra quests such as the pale lady. or collect all artifacts (unique weapons) like the headsmans axe. skyrim is a big game indeed

If I were to blow straight through it all, probably about 48 hours.

My first character, I did everything (except Dragonborn, he didn't make it for that...) and that was about 300 hours total.

What?

do I sense competition.

If I were to play through all of the guild questlines, the CW, and the MQ, it would only take me 48 hours.

300 hours on average.

A little over two years have passed in my game, so I guess that's over a thousand hours of play. It feels like time wasted to me though, looking back on it now.

270 and counting