I think I understand now, after having a look around.
I currently have around 50 dvds in my collection 1/2 from the uk and 1/2 from america, I used to use my computer to play them, but now I want the proper thing.
I was going to get the multi-region Sony 735 but from richer sounds but I'm now a bit worried thats it's not going to play all my disc's should I get the Pioneer DV636 or the Panasonic DVDRV60 instead !!
Please help