My To Be Read list is literally that - the books on my shelf that I already own that are waiting to be read. The reason I keep a list, and I've put them in order as well, is because I used to leave the scattered among the many shelves in my house, but when I finished one book and was looking for the next, I used to spend ages dithering about which book would be next, and wasted precious reading time. I finally decided to collect all the books into one bookcase so that they're all there waiting for me, and although I've got a order I plan to read them in, I'll happily pick something else off the shelf that takes my fancy if I feel like it.
However, my wishlist is a completely different kettle of fish. That's the list of books that I've heard about, read about, or been recommended that I would like to buy. In theory, I take this with me to the bookshop and would pick books from it when I'm in a buying mood. In reality, I forget all about it, wander aimlessly and pick up whatever looks appealing at the time. For example, today I bought four books, one was the next in a series I'm already reading, one was a book on my wishlist by an author I've read some other books by and really enjoyed, one was a book that I'd seen a lot of coverage for as it had won an award and looked fascinating (these were all on a 3 for 2 offer) and the final one was a book I'd never seen before, by an author I've vaguely heard of, but just looked fascinating.
Don't take this the wrong way, but surely as a reviewer, you're hoping to encourage people to buy good books that they might never otherwise pick up? That's certainly why you're being asked to review the books. I agree to a certain extent that it's great to pick up books without any preconceived ideas or without being influenced by other people's views, and you're in quite a privileged position to be sent books for free to review without knowing what the next style, genre, author will be, but for me, I sometimes want to know that I'm sharing the very individual reading experience with people I trust and whose opinions I respect by reading books they've recommended.