What is the preferred way to cache static files these days? (i.e. ccs/js)

1. Recompile with slowfs module
2. Serve css/js through php backend and use fastcgi_cache
3. Create additional nginx localhost server and proxy_cache from nginx backend

Drupal6 has a nasty habit of recreating its aggregated css and js files (i.e. css_[md5hash].css) on module updates, etc. Which means cached dynamic pages end up pointing to non-existent files. An nginx cache could protect against that problem, but I'm not sure of the best way to do it.