In reply to Andy S:
I think the choice of guidebook is really dependant on what you want. If you are planning on going valley cragging, and venture a bit higher in the Aiguilles Rouges, the Burnier (Vamos) valley guide is brilliant - and the format is a bit smaller so it fits in your pocket!
Rockfax isn't bad - it covers some of the more popular areas on the Mont Blanc side - but this is a much more serious proposition, and you need to have your alpine wits about you.
The Piola guides to the Aiguilles Rouges are fabulous. You could spend a long time (years) climbing there and there are some big and adventurous routes. I haven't used the ENvers guide so I can't comment.
Finally, there are a bunch of more specialist guides - a couble of granite guides (inc specialist crack guides, and IIRC correctly a Mont Blanc Plasir (i.e. mid-grade) guide.
Personally, I would say that if you don't know about climbing in alpine settings, then Rockfax is possibly a bit wasted on you. Get the Vamos guide, climb in the AIguilles Rouges: Les Gaillands, Les Cheserys, Montenvers (OK that's the other side) and Brevant.
There will always be another opportunity to come back - and Chamonix is probably not the place to start thinking about alpinism. It is too big and too scary (I know - my first alpine trip was based out of Snell's Field - aged 17!).
OTOH, if you are comfortable in an alpine setting, and want to spend a couple of weeks all over the valley, including up on the Chamonix Aiguilles side, then Rockfax is pretty good.
Steve