This game is certainly my favorite RPG of the 2000-2009 era in gaming. It built on the successes of earlier RPGs such as baldur's gate and neverwinter and really decided to make a gmae world worth exploring.
I've been playing the game every so often since 2009 and there are certain aspects of the game that don't hold up, like excessive pop-in texturing, long (and progressively longer loading times with larger save files) loading times even on PC, which is a sad, sad thing. When one has a hybrid-SSD, a game should not take 5-10 minutes to load an action sequence. Which leads me to believe it is a memory leak, or a fault in the programming, as this generally seems to follow a set pattern. The length of the load-time increases in proportion with two variables. The first variable is how long you have been playing the current character, and the second variable is how long you've been playing in the current session.
Also, random encounters are a crappy thing to do to a player. Just look at every JRPG. Did anyone think that was a good idea? And...some of the animations are cheesy and overdone.
Okay, I got all the bad stuff out of the way first. Everything else is completely masterful. The art direction, music, combat/tactics, and story progression are legendary. I have yet to find a game that has this massive of a scope and yet allows consequential decisions by the player-character/warden.
Even in 2009 I thought the Origins were an awesome addition, even if they didn't altogether seem to change the overall outcome of the game. They were subtle and yet informative. They helped shape a person's backstory, and also changed the way NPCs refer to you throughout the game. I played as Dwarf Noble, Dwarf Castleless, Human Noble, City Elf, and Mage. The only one I've yet to do is Dalish Elf. I can't wait for inquisition to come out, since i have a Dwarf Female Castless rogue (warden plus warden commander and all dlc) imported to DA2, and ready to go for DA:I.
Mass Effect capitalized on the meaningful companions and meaningful choices formula, but DA:O took it to a new level (minus the whole gifts charade). Each companion you pick up (and many of them aren't even required) are unique and interesting. They interact with each other and with the world around them. They respond believably to the events that your Warden gets into, and are all worthwhile investments of your time. Get to know them. Even Morrigan, and especially Alistair and Leliana. They're all wonderful people that feel real.
In the end, though, what keeps me coming back to the game is that there aren't any other games out there like it. There are some that have tried, but oh how they've failed. I'm looking at you, Kingdoms of Amalur. Even DA2 couldn't compete with its predecessor in terms of replayability and meaningful consequences.
It would be exceeedingly rare for two separate gamers to have two Wardens that made all the same choices. I'd say the odds would be somewhere in the hundreds of millions to one. There are hundreds of small choices, and quite a few large ones that not only affect the ending, but leak over into the DLC and Awakening (and somewhat into DA2). This is what makes this game a masterpiece. It singlehandedly makes you forget your life and brings you into the fold of Ferelden, Amaranthine, and Thedas itself. Only the Bethesda games can claim to have as large a scope, but DA:O will always win in excecution in my book.