My preference is to make a base ami that's configured with puppet and a couple core user/keys. I make this instance automatically hit our puppetmaster and use things like security_groups and user data to figure out what type of node it is. One of the things that puppet installs is a script to generate a new ami from the built instance, this script optionally deletes the puppet package.
Now you have an easy way to build your ami from the ground up, you only need to worry about core OS package enhancements on the base ami, and you can use your created AMI with autoscaling behind an ELB.
For VERY rapid changes - direct git access is optional (even on startup for current code pulls), but I tend to side with the Netflix guys and focus on an AMI as the minimum unit of deployment.
Now you have an easy way to build your ami from the ground up, you only need to worry about core OS package enhancements on the base ami, and you can use your created AMI with autoscaling behind an ELB.
For VERY rapid changes - direct git access is optional (even on startup for current code pulls), but I tend to side with the Netflix guys and focus on an AMI as the minimum unit of deployment.
Check out asgard to make this easier (senseless self plug: I built an asgard ami this weekend - http://imperialwicket.com/netflix-asgard-ubuntu-1204-lts-ami...).