i have a few in my top 5, but the best RPG ive ever played is Dragon Age Origins, you have a good bunch of dialog, romance, companion reactions based on your actions and they being present when you do them. Dialog and storywise is by miles better than mass effect. Romancing a character takes time in DAO and you can change romances (not like in me games where you had to stick with the first girl you say "hi").
Also characters remember what you said in almost every situations, not like in ME2 when Mordin acted like i was against the genophage even when i agreed to it in every dialog.
The gameplay is fantastic, like a WoW where you control 4 character at the time. you could manually control companions and program their "combat tactics" very precisely.
The micro stories have their twists, but the general story is the overdone "a blight is taking over the world" thing, but the game is long enough so you wont finish it in a few days.
The DLCs are very disappointing, i had my hopes up for "Awakening" (largest dlc campaign), but you only had the least appealing of your old companions, no romance options,and not even a cameo of your romantic interest of the original game (i romanced leliana and only got a letter of her saying she was visiting i dont know what monastery).
Now, Dragon Age 2, they took the dialog part and replaced it with ME dialog system, a huge setback, you had less options and choices rarely mattered (though your companions still "reacted" to what you said while they being present, it was in much lesser scale, and even more, if they "hated" you, they only gained a different skill than if they liked you).
The characters were bland, and even more the females, where you only got a whore and a shy girl.
i loved so much when i got to kill that madafaker of fenris, god i hated that character so much.
Also Hawke.... other factor that ruined the game
1. a character with a name (not chosen) is always a con, thus it makes it harder to relate yourself to him
2. he had a history and a family which you couldnt choose
3. can't choose his race
4. i preferred when the main character didn't talk (while the rest do ofc)
other main factor of the game is the recycled scenarios (90% of the game are the same rooms with doors locked/unlocked in a different sequence).
but one of the worst things was how fucking fast years passed, i mean, you farted, poof, 2 years. i think that in the totality of the game it passes like 7 years or more, can't remember exactly, time in which i could only think "what is my DAO hero doing right now?"
and your choices in DAO had very little effect.
i really hope that DA-3 retakes DAO system and character, or at least starts a new character, but not Hawke