I personally feel the term RPG is misused to describe a lot of games. I personally feel that to put the tag RPG on a game you need choices that clearly effect game play and the story line depending on the choices you make. I see quite a few games given the tag RPG simply because your character uses swords and magic or you might have some level of customization as your character levels up. If the story line is linear it is not a RPG for example final fantasy fits this bill perfectly but i see it is often tagged as a RPG. Mass Effect In my opinion if you liked the game or not does fit the bill of a RPG since the choices you do make clearly define your character and your adventure also the fact that the choices you make have a effect on the other games in the series.
This is something that has slightly irked me for awhile since I am admittedly a DnD geek so my opinions might differ from others.
I am curious to see what other members of the community feel about this subject.