I too was thinking about the Witcher, but my RPG backlog is large enough.
I hear you... especially with Steam and all their sales over the years; overwhelmed with so many games, the desire to finish them started to feel more like a chore/job than for entertainment value haha -- learned that it can be fun and rewarding to stick to ONE game and crank it out (at your own pace of course) -- did this with Mirror's Edge, Trine, Metro 2033, etc.
Never played the Mass Effect's and with ME3 on the horizon, I'm gonna hit up ME1&2 :P