At the top of my wish list there is a deployment tool for web applications like capistrano / mina for Ruby. I ended up writing my own for the project of a customer. It's been running for a few years now.

Same customer, another project, I'm experimenting with a deployment system based on git format-patch. It copies the patches on the server (we have only one server) and applies them with patch. Then restart the web app.

It's fun to learn the internals by rewriting the tooling but a good tooling to start with would be better.