The BlueRay drive in the PS3 is definitely a bonus BUT it does add a substantial amount to the price tag. Personally I can't justify $600 for a game console, but I can justify $400.
First and foremost, the 360 and PS3 are game consoles. Sure the ability to play HD movies is a really nice feature, but it doesn't affect the gaming aspect of the consoles in the least. The size of current dual layer DVDs is plenty large enough for games. The compression algorithms that game developers use are pretty crazy, and they can fit a lot of game onto a single DVD. I doubt we'll see a need for larger discs in the next 3-4 years. If we do, Sony was right and Microsoft was wrong. One thing worth mentioning however, is that the BlueRay drive in the PS3 is slower than the DVD drive in the 360. If I remember correctly, the 360 reads at around 16mb/sec while the PS3 sits at 9mb/sec. That means the 360 can load games faster.
Technologically speaking, I've read several articles that declare the 360 a more powerful system than the PS3. The gist of it is that the Cell CPU in the PS3 is an incredibly powerful CPU, but absolutely sucks when it comes to games. If the PS3 had been built to crunch numbers, run SETI, basically do supercomputer type stuff, it would run circles around the 360. As it stands, the 360's CPU is a much more efficient design for games. The GPU in the 360 is also more powerful, featuring a 10MB z-buffer that the PS3 does not have. I have yet to see a PS3 in action, so I have no idea how these claims work in practice.
Josh