Cards are out in Japan and are said to already be released in some places in North America, the rest within the next couple of months.
A trade in controller option would be really good, but I probaly wouldn't use it.
We don't need Backwards compatibility on the 40GB, just get the 80GB if you want it.
HD Movies, TV shows, etc. would be a great thing to have, but once again I wouldn't really use it. I also think Sony wants people to buy blu-ray movies instead of downloading, so I can't see that being added.
Offering IPTV and TiVO functionality through a firmware update would be a great addition.