I use IE out of habit sometimes, but FF is far superior and use it for critical stuff like downloading and projects.
I use the FF Add on
IEtab and Lauchcast works perfectly with firefox.
I have been using Last.FM as well and find it to be fine service
though I am not a Ipod person and don't get the full benefit,
I have found many bands and artists with Last.fm.
I still contend that if you are able to use Launchcast(not shoutcast ..thats another radio service.....
) that you will find it very intuitive and a great
alternative to add to your listening arsenal.