How often do you need to endure that 20-30 second startup time? Is it every time you change anything?
It's a huge productivity killer for me. And as other comments have stated, it's surprising this issue is not discussed more.
Keep console open and use reload! when you change your models, for starting a server I don't have much other than keep it running the background, running a test -- use spork, migrate your db and run rake tasks -- try to take advantage of the fact that you can specify multiple rake tasks at a time; "rake db:migrate db:test:prepare"