My favourite vocaloid songs are 'Kagome Kagome' and 'Alice of Human Sacrifice'.
There's also like a metal version of Miku that I forgot the name of, and some of those songs are pretty cool.

I downloaded the freeware one, I forget which vocaloid it was, but the program itself was hard for me to work with, so I couldn't get it to sing much of anything. Too bad, because that would have been a fun music program to mess about with.

I probably mentioned but before I got early onset arthritis I played guitar and bowed psaltery both for fun and semi professionally in a couple of bands. I like having new instruments and programs at my beck so I can add interesting new touches to songs when I write them.