Quattro. I went to an exceptionally good grammar school and if I lose my job and my DC's are able to transfer there at 11, I will thank my lucky stars for the safety net. However, whilst I can continue to afford private education I would not dream of moving my children to grammar, mostly because of the pastoral care an indie provides, partly because I think private schools generally stretch pupils in the areas in which they are talented in a way that grammars do not (be it sport, drama, academia, music), and partly because I think that smaller indies are able to stamp on cliques and bullying (if the school itself is so inclined to do so) more efficiently than the larger grammars. I emphasise the 'if inclined' bit because I think this really varies widely between schools.
I know many people who run business in my local community or are involved in the community in general, and the one thing they always comment on when discussing schools is how exceptionally happy children are in my DC's school and that was another factor for me. That kind of quality can't be written into an ISC or Ofsted report but it really counts - but it is difficult to get a feel for this I guess.
champagnedahlings - I disagree that bubbles rise to the top. Completely. In another thread a while back there were some stats showing that there were (if I recall) around 40,000 extremely able children in the state sector at age 11 versus 7,000 in private education (as tested using SATS), but that when that particular year was tested for A level results, and specifically for the gold standard of 3 A's, the state schools managed I think around 10,000 top results, and the independants managed 7,400. So bright children on the whole appear to be disadvantaged by the state system and do not reach their potential (if we are to use 3 A's as a measure of potential). If those results were to be further broken down into traditional versus modern subjects, I think the differential would be even greater.
Abby - I have found your posts very interesting and slightly depressing. I think everyone on this thread will agree that - ceteris paribus - a child with 3 A's from a crap comprehensive is going to have a million times more potential than a child with 3 A's from Eton. Even though my DC's would be disadvantaged by positive discrimination, it kind of seems fair to me to see state schools get some sort of preference when they achieve top results?