I guess I'm kind of weird in that I do not have a canon play through, but I have canon play throughs for classes; warrior, mage, rogue. I always romanced Alistair and kept him in the wardens for my mage and warrior play throughs. Since my warrior is a city elf, she thought the best way to give Alistair the family he always wanted was to stay in the wardens. This way she and Alistair could make trips to the alienage to visit her family any time they wanted. May mage was a bit more practical. Since Alistair was nearly a Templar, she thought it best to keep him close just in case she ran into a fanatical Templar who would "overlook" that she was a warden and execute her as an apostate.
My dwarf commoner had Alistair marry Anora and stayed his mistress. She saw the wardens kind of as a surface version of the Legion of the Dead and since Alistair was of the "noble caste" he should rule and marry Anora. She could stay his mistress as that was pretty common in Orzamar. She also sided with Beheln so her sister would be taken care of. My dwarf may have left Dust Town, but she was still a duster. Kind of sad really that she couldn't get past that.
The one fun thing I did with my mage play through is have my mage Hawke side with the Templars and become Viscount. I was highly amused at the irony of the final scene where the Templars knelt before my Amell.
Since I'm such a "goody-two-shoes" the rest of my decisions are pretty much the same; saved the mages, saved Redcliff, freed Connor/Anora alive, Ashes pure, killed Flemeth, Alistair did the dark ritual, PC killed the AD, Loghain dead, elf/werewolf peace brokered, etc. I do have some variations, but I'm not sure whether I'm going to make a world state for them just yet. I think 300 hours of play time will keep me occupied for awhile.