You may want to consider a US ps3.
Some games have hardware based region "selection" which can result in differences. One example of this is uncharted, where playing on a japanese ps3 will remove the blood from the game and give you more limited language selection options. Disc contents are the same from region to region so the differences are applied based on what region your hardware is from.
If you have no interest in japanese ps1 backwards compatability (disc based) then just get a US one, especially if you plan on playing resident evil or anything violent on it.
as far as blu ray goes, there are 3 regions: US and Japan, PAL, and Dirty Commies
to recap:
-ps3 games from all regions work on all ps3s
-depending on the game, there may be in game differences depending on what region your hardware is from
-disc based backwards compatability region is dependent on console region
-BRD's are regioned, but theres not as many as DVD, US and JP are both region A