Are you doing this entirely by hand, or are you going to use shit like CPanel/Webmin/etc to manage it?
Most of those tools
require 1.3.
I use 1.3 because hacked up with lingerd and a few handmade things, it's still faster with it's prefork model than 2.x, and (as of v4) was safer with PHP.
v--
mod_bandwidth can help you, and doesn't leak quite as quickly as mod_throttle.. but if you gracefully hup it twice a day, it doesn't usually matter.