C64 Framework

I'm currently cleaning up my new C64 framework and just now its pretty simple. A basic multiplexor with "N" sprites multiplexed (currently 16) and rasters going and I was wondering what else I should add?

Got any ideas as to what the basic frame work should contain? It should be fairly broad scope as theres no point in specialising stuff since it would get ripped out pretty quickly by anyone actually using it, but if you can think of some common stuff you always use, like keyboard routines, joystick functions and the like... then I'll probably add them in too.

So let me know what you think would be handy....