i would also like to add that the benefit of doing it in a lisp like Common Lisp is that you get Smalltalk-type interactive development environment (if you want to see how cool this can be on a system level try StumpWM, fire up SWANK, and live-hack your window manager), AND a language with implementations (CL is an ANSI language specification abstracted from any one implementation) that have C-level benchmark speed, eg. SBCL