The mp3 player I'm using on this blog is flash player made by Jeroen Wijering [ link]. Since it is flash player, it is very light and use very small system resources.
If you want to use, download the player here. zip file includes necessary files for player, instruction readme file, and source file "fla".
You can use it with two styles; one with playlist and visualization, AND another one for just single song. I used single song style on this blog. it is very simple. [see the demo at "Song of the week" above.] if u want to use "single song style", u need to upload "mp3player.swf" only.
Actually, I like the one with playlist and tested it on my google page . But it doesn't read the playlist when I load the player from my blog. I think it might work if full URL of playlist is refered in swf file. (You can edit source "fla" if you have Flash 8. ) [Can you help me?]
If you think reading readme file is confusing, here is sample code for "single song player".
Hope this helps.