High Scalability Building bigger, faster, more reliable websites.

Hi, I am interested in some experienced advice for choosing switches for a colocated 2-tier architecture. I have the hardware chosen for the webservers, app servers, and db servers, but need some advice on the network switch in between:

colocation port -> firewall(load balancer) -> 2+ web servers (app servers) -> gigabit switch -> DB server(possibly cluster for future expansion)

the question is that I am just starting out, i wonder which rackmount gigabit switch to select for the private LAN between the app server -> DB servers. Do I need managed for that? Cisco switches are the best, but they are the most expensive...I am looking at possibly using Dell/Netgear gigabit switches.

Thanks for any input