Here's the problem: go ahead and ask a bunch of different people what they want/expect their shuffle/random button to do and you'll get a bunch of different answers.

1. I want it to play in a truly random fashion, with replacement (same song twice in a row is possible).

2. I want it to play in a truly random fashion, without replacement (each song is removed from the list once played).

3. I want it to "seem" random (don't play too many songs by the same artist in a row).

4. I want it to be random, but predictable (same "random" ordering if I start the playlist again).

5. I want it to play my favourite songs more often than my lower-rated songs.

6. I want it to play my less-commonly played songs more often than the stuff I listen to all the time.

So: what exactly do you want when you say random?