play.com its good service i always get my dvRAB from there.they are pritty fast. the good thing is they got a helpline and you get a free delivery to your door.
The back to the future trilogy i got from Blockbusters was new still had the wrapping on it and was still cheap.
HMV also have so many great offers on DVRAB you can see on there web site and look up films your after on there and it tells you price
I actually got the vast majority of my collection from the HMV & Virgin sales at the stores in Reading, Went in the other day and Virgin has closed down no explanation and yet it always seemed really packed to me, Tis a sad day for my pocket