haproxy and nginx are the best of the lot. Consider also ipvs for layer 4 load balancing. One question that will help decide how things are structured is SSL.

haproxy and nginx are the best of the lot. Consider also ipvs for layer 4 load balancing. One question that will help decide how things are structured is SSL. If you need it, putting haproxy up front gives you a bit of trouble -- haproxy doesn't support SSL (though it will blindly forward SSL at layer 4 if you want). So you'd need stunnel, nginx, Apache, or something else up front to decode.