by default, apt-get install mysql-server (nothing change, work ok)
apt-get install nginx (default)
all configure by default
now configure nginx to use php5-fpm to serve php file
this will use aroung 70M ram,
That is why I said thttpd + sqlite < 1 M ( very light )
It just depends what you expect for load or response times....but perfect for development
so far I know nginx has also in his docs that you can use thttpd for the cgi processing.
yeah raspbian ...... great distro for the RPi
thank you mpthompson !