The media player sounds like a neat project!
How do you map the volume to 40 segments? Integer division is slow, but not a disaster. Floating point IS a disaster in terms of performance, of course. I suggested 32 segments and >>. There may be a way to think in terms of 64 segments and >> with the result ending up in only 40 real segments; I'm usually too dull to work tricks like that out.
If you were really willing to dig into Liquid Crystal you could take what I had posted with the busy flag, stop making it a library but pull it into your own program. At that point you know which pins are used and you can combine those 2 things with issue 140 in the google code forum for Arduino to use AVR ports instead of digitalRead and digitalWrite. This would make checking the busy flag feasible, faster than ever, and hugely speed up some other small places. You would need to use RW, so you'd lose that pin. There were some delayMicroseconds(1) lines that I commented out but never actually removed from the source which would have to be reactivated. That would be a lot of work but the Liquid crystal speed up would be roughly 40% over what it is now, I think. As long as its a library routine, the AVR ports/issue 140 thing seems unavailable.