Which Banks book should I start with? I was going to start with the Player of Games after your comment, but it turns out it's part of a series, and Consider Phlebas is the first one. Does it matter?
I'd suggest Player of Games first; I found it better as an introduction to the Culture. They're not really a series as such; his Culture novels share a setting but don't share any characters (well, almost none) or any particular plot continuity, so you certainly don't have to read them in order.
I'd suggest PoG as a starting point to explain what the Culture's about, which I think it does better than CP because the main character in that is not of the Culture. YMMV though.
No, it doesn't really matter. Each of the Culture novels is basically standalone. They occasionally reference events amongst each other, but more in an "this is an interesting story too" manner.
I'd suggest not starting with the Culture novels. The Algebraist is more accessible because it's not constantly referring to a mysterious super-organization that's driving the plot.
The Culture books are not really a series so much as a collection of stories all taking place in a single imaginary universe. Plots and characters from one book occasionally turn up as background details in another, but there is no reason to read them in order.
I've read in a Amazon review that it is recommended to start with Consider Phlebas, then The Player of Games and finally Use of Weapons (as a first start into the Culture, that is).
I've bought them three myself and will read them in this order.
Use of Weapons is great, but the writing is poorer than the other two.
Heh. Interesting. I'd say exactly the opposite myself. Not that I dislike the other two - PoG is one of my faves of his SF work - but to me UoW is a vastly better work of literature, both in structure and character development. Less full of SFnal goodies than some of his later work, but all the better for that in some ways.