I'm ranking the games basing my judgement on how much I liked them during my first playthroug. If I were to replay all those games right now the ranking would be much different: for example I would hate pretty much all baldur's gate interface and that would make it drop a lot in the chart.
Main Games
1- Baldur's Gate II
2- Dragon Age Origins
3- Baldur's Gate I
4- Dragon Age II (Crappy characters, crappy setting and crappy level design, but best combat system in the franchise so far)
5- Gragon age Inquisition (I see the effort developers put in this one, but I sincerely can't enjoy it... too much grind)
Expansions and DLCs
1- Legacy (best boss fight of any Bioware game I ever played, great main villain with even a better voice actor than the one in Inquistion)
2- Awakening (hits the second spot for the sheer amount of content)
3- Throne of Bhaal (great conclusion to a great saga)
4- Tales of the sword coast (good amount of content)
5- With Hunt (Moneygrab ****, but I'm a fan of Morrigan, what could I do? I loved it).
5- Stone Prisoner (I loved shale, and this is good value for a DLC)
6- Warden's Keep (Enjoyed the story, but the keep was disappointing... I wanted something like Skyhold)
7- The exiled prince (didn't like this one, Sebastian is the worst companion among a roster that is already bad by itself)
8- Return to Ostagar (This one was my personal nail in the coffin on DAO DLCs until Witch Hunt was released... too much to pay for 2 hours of meaningless content)
9- Mark of the assassin (hated this one... I still wonder why I bought this Felicia Day commercial)
Didn't play the others.