First of all, great plugin. It's replacing WP-Audioscrobbler on my site because it looks like development there has stopped. Installation was dead-simple, caching works beautifully and it is overall a great script.
The only change I made to the plugin (only because it isn't a configuration option) was to disable the default stylesheet. I already have some formatting for other plugins I want it to match up with, and I didn't want to have to fight it with !important tags everywhere
So, at the base of the file ...
# add stylesheet(s) to head
// Hack, not interested in the default styling
//add_action('wp_head', 'lastfmrecords_stylesheet');
Just a thought for future enhancements.