what motivates you to chose a book? There is a belief that we don't chose our books anymore, instead we read what R&J tell us to read, which is, by personal experience, something I find to be totally untrue.
I do look at the books they recommend if I see a sticker on them but they do not decide for me what I read. Often I will go to the a-z shelf and spend some time going through back covers until I find something I want to read.
I'm more influenced by the Canon than Richard & Judy, although I don't necessarily think that is any better.
What influences you?
Also, there is the old adage: don't judge a book by its cover - do you ever buy/loan a book on the basis of the cover?
There are certain authors whose books I will buy - purely because I have read other books of theirs, and know I will enjoy them, Ian Rankin and Karin Slaughter being examples. Other times I go for recommendations of friends, although 9 times out of 10 I don't enjoy them. Or what our book club reads, again I don't always enjoy them. Sometimes I do just read the back cover and think "hmm that sounds good", and buy it.
I don't actually watch R&J so they certainly don't influence me
Canon is good, I have a good friend who buys lots of books and lends what she thinks I will like, sometimes it works and sometimes it doesn't, and like you I browse through a-z, might read the reviews occasionally and stumble on something great.
I don't really watch it either. I think people are refering more to when you go in the shop it is very evident what R&J think you should watch by the marketing effort on their behalf (I think stats would tell you books they support sell a lot more than others).
I also was once told to read the first page to see if you like the writing style, although I have to say I rarely do that.