I don't care which version ps2 I own. As long as it has a good laser and it is not a v12 because of the unsolved burnouts. It doesn't really matter which version you get because if you know how to mod it, it will work just like any other ps2. So bottom line, any with good laser. I think people are favoring v7 too much. It is probably good for a person who never modded a ps2 before since it has easier soldering points. But to someone who can solder, it's just another ps2.
Someone will bring type of lasers up as an arguement but even v7 have crappy hd7 lasers.