suggestion to choose a load balancer

[LinuxNewB]

Hello,
I would like to set a load balancer for my 2 webserver of heavy traffic.Could any of suggest me to get a best brand? and is
(Foundry ServerIron XL and 4G-SSL network load balancers) a nice one?

Did any one familiar with layer 4 and 7 load balancing?what is te difference between them?

[ogletree]

I know F5 networks is one of the top makers of that kind of thing. Many of the top sites use them including the US Gov.