Pike, whilst I can't speak about all the services on offer in the USA (we here in the UK don't get Prime Music) I spent the past 6 months effectively doing Amazon Customer Service for Prime. In the UK they have Prime Instant Video (PIV) which is like £5.99 per month or £71.88 per year when you do the math, for like £7.12 they deliver anything fulfilled by Amazon to you for free with next day delivery too which is like £12 per order normally.

In short, Prime most certainly is worth it, not to mention Prime Instant Video in the USA includes a lot better movies than the UK.