Much of stuff here on peterbe.com is done that way. I benchmarked the hell out of that too and found it much much faster than Varnish and Varnish was much faster than Squid. It's a bit clunky to invalidate but when it works it works wonders.
if it's caheable, put it in memcached and nginx can fetch it directly, without calling the app. in fact, you could even write to a ephemeral file; nginx is just as fast on the filesystem as memcached on RAM
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Much of stuff here on peterbe.com is done that way. I benchmarked the hell out of that too and found it much much faster than Varnish and Varnish was much faster than Squid. It's a bit clunky to invalidate but when it works it works wonders.
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if it's caheable, put it in memcached and nginx can fetch it directly, without calling the app. in fact, you could even write to a ephemeral file; nginx is just as fast on the filesystem as memcached on RAM