Simple is Best

don't use squid as reverse proxy(like squid) before a mod_deflate/mod_gzip apache/lighty/web server, especial for dynamtic pages, otherwise the reverse proxy cached page will be special linked to only one client(because of ziped page contain http cookie ?), thus the efficiency of the proxy will become terrible and the load of the behind server will increase a lot(depend on cached your pages and vistors).
deep in finding a solution.