In my opinion the difference between sens 555 and 595 is very small. My friend thought it would be cool to get 595's just to one up me. Couple days later at a local Halo LAN we compared the two it was really hard to distinguish them. We had a couple people try both of them and tell us which was better and they couldnt decide. Mind you this was only Halo 2 so you know maybe movies and music sound much better on 595's or something its completely possible. Just thought I would throw that out there, maybe save someone some money.
Also Bioshock with headphones on at night is downright freaky man I almost jumped out of my couch this one time.
I'm a Halo 3 semi pro. seriously.