Good Ruby on Rails Tools

I'm looking at the following tools to add to my Ruby on Rails tool chain:

Continuous Integration

RunCodeRun at runcoderun.com
CruiseControl by Thoughtworks

Scalability

I'm excited by the products talked about at the NewRelic scalability blog. I saw the first episode and am very psyched about bullet by Richard Huang.

Metrics & Monitoring

Can't wait to try out Caliper for Ruby metrics and NewRelic for monitoring

I'm using SVN on a few projects, but I have been in the promised land and can't wait to get back to git, so let's add GitHub to the list.