When I played DA:O the first time, I had already 80 hours of gameplay before I entered Denerim the first time.
The only main questline I did at this time, was that with the elves.
I wrote a post in a German forum, praising BioWare to return to old traditions and give the players really loooong games. Then I was a bit too enthusiastic, because I predicted the "end of the dumbed down 20-30 hours RPGs".
Man, was I wrong.
But that aside:
My first run through DA:O (hard difficulty) took more than 150 hours. It was shortly after release, so the only DLC was the Warden's Keep and The Stone Prisoner. Of course you can assume, that I literally looked into each barrel, under every stone, talked to everyone and did all sidequests.
The next runs were shorter, but never below 50 hours. As a matter of course I never ever did a so called "speed run", because this I consider as unforgivable sin for a true RPGer.
Thank you!!! I thought I was the only one.
People made fun of me and accused me of lying on the old Bioware forum when I said it took me over 160 hours the first playthrough. They just said "That's impossible. The game only has material for 20-30 hours of gameplay." and "There's no way it could have taken you so long" and "You must have accidentally put and extra 0 to that number" and "My playthrough never gets longer then 20 hours and I do everything in the game" "Non of my playthroughs have been longer than 12 hours" aso aso. Finally someone who can believe me! 
Since the old Bioware site is down I can't check the numbers uploaded so I had to start the games.
Dragon Age: Origins
1: 162 hours
2: 155 hours
3: 103 hours (was going to be a speed run to have something to play when I was without an internet connection but I don't like speed runs and I'm really bad at them, as you can see.
)
4&5: 21 hours so far per playthrough. I was plaything these at the same time because I wanted to play and Dalish and and Human at the same time and could not decide.
(was on the first major quest after Lothering when Skyrim was released and never picked up again, mostly because I deleted all the DLC and M$ changed their policy making it impossible to download them again. Then I got the game on PC and started a new playthrough)
6: 2 hours so far (Still in the Human origin. My PC broke down and when I finally got it fixed I had started on DA2 again, but I plan to continue later.
So far I have only played Human Noble, City Elf, Human Mage and started on Dalish Elf. I wanted to save the Dwarf origins until I play through the game at a later date to have something new to look forward to then. I plan to still be playing this game in 10 years or so. 
Dragon Age: Origins: Awakening
1: 48 hours
2: 43 hours
3: 23 hours (a speed run because DA2 was coming out in a week or so. By this time I knew the game inside out)
About 3-6 hours per DLC on the other ones.
Dragon Age 2
1: 56 hours beginning of Act 2. Never finished this one. I was waiting for the DLCs so I took a pause and when I resumed I decided to start a new game because I wanted to play a Rouge.
2: 136 hours.
3: 128 hours so far (have half of Act 3 left)
4: 51 hours so far (end of Act 2) Lost my internet connection so I couldn't continue my 3:d game so I started a new because I still wanted to play. This one is a speed run because I wanted to play an aggressive before DA:I, but I usually don't do speed runs.
I have always taken my time playing RPGs. There's no Bethesda game I have finished under 450 hours (and still I had to skip lots of places to finish before the next game's release), no Final Fantasy under 140 hours (FFX was at 180+ hours both times and FFVII was 99 hours half through Disc 1). Nice to see I'm not alone. 