I own both a 360 and PS3. I use my 360 for games and I purchased a PS3 since I needed a dvd player to replace my broken one in the living room and my parents thought that might as well get a blu-ray player since it might become the standard if it doesn't go the way of laser disk, and since the PS3 was cheap enough to purchase as it's a great upconverter, we bought a PS3.
The three options you choose don't make sense. Why would people purchase another console because they don't want to pay for multiplayer? You don't have to play multiplayer and the entry fee for PS3 is higher anyway. It hurts less to pay 50$ per year a pop than to pay 50$ more on top of 350$ at the same time. Then, the desmise of HD DVD had nothing to do with 360. It was an optional accessory. You choose PS3 for bluray or you choose 360 for gaming. I don't see people choosing 360 for HD DVD. Then, your last option is last generation. It has been almost a year since the falcon equipped 360 has been on sale, which has a normal enough electronics repair rate.
For the real reasons to choose PS3 over 360, I would have gone with those choices:
1) free bluray or free gaming machine with purchase of game machine or bluray player respectively
2) GT5, MGS4, FF13
3) you write M$ all the time
