President Chirac, I beg you
Some CAP facts and figures
The official arguments for the CAP

Doha Round and developing nations
Why do the British prefer cheap food to rich farmers? by Gary J
How bad is the CAP? Oxfam say it's very bad. by Colman

In the long run, we're all dead. John Maynard Keynes

G20 - emerging markets asking for an opening up of the markets of the developed world

Cairns Group - countries with very competitive agricultural sectors and strongly pro free trade in that sector (one third of world ag. exports)

US and EU - the traditional protectionists

G10 - highly protectionist countries - and significant importers - keen to protect what remains of their agriculture

G33 - weak ag. countries who ask for specific protections as a  total opening of the market scould devastate their economies.

The accompanying article in Le Monde flags various points:

• the WB estimated that a full opening of ag. markets would have a net global benefit of 182 billion $ by 2015. However, this would be unevenly spread:

• the big winners would be exporting countries like Australia, Brasil, Argentina, which subsidise the agriculture little, and are highly specialised, and competitive, in a few products (beef, milk, sugar, wheat);

• the big markets (US and EU) would see losers amongst producers unable to cope with competition, and winners amongst consumers, who would see lower prices (or amongst the distribution chain, if lower import prices are captures there...)

• the non competitive third world would likely be a net loser, as they would lose their preferential access to Europe. The volumes are too small to be significant in any case, except in very specific cases like cotton producers in central Africa which would benefit from an end to export subsidies form the big 2. After losing out to China on textile, these countries would now lose to Brasil or Australia on the agricultural front...
  

The market access as you pointed out means little, but the export subsidies is a significant, even if largely symbolic, step.  The hitch of course is that the elimination of the export subsidies makes the real meat - elimination of production subsidies - all that much harder.