I've given up on iPlayer. Whatever it does when it sets itself up initially has caused me to experience extremely slow start ups. It could take 3 or 4 minutes before I could use my PC. I've just removed it and things are back to normal now. Don't think that I'll go there again until we're through the beta stage.
On the odd occasion that I used it, WMP seemed to work best, but I suspect that if it's set to expire after 7 days, that's exactly what it will do.