I have no problem with nudity, except when developers put them in to say "Look! Breasts! Look how mature our game is!" pointlessly.
I will admit, that a part of my horny 16 year old self enjoys these scenes, but mostly I feel that scenes such as in Mass Effect have not yet evolved to the stage of those in Movies. While videogames have advanced leaps and bounds, this is still one barrier that has not yet been broken down.
I can't remember who said it, but at the moment sex and nudity in video-games resemble awkward puppets, no emotion or application. One day they will be an acceptable and tasteful part of the gaming medium.
"I think it passing odd that I am loved by one for a kindness I never did, and reviled by so many for my finest act." ~ Jaime Lannister