I've been hankering after this for a while and finally got it from the friendly guys over at the cycling plus forums. The table helps to grade your power output per kilogram of weight either as peak power over a given period or as Functional Threshold Power.
Anyway, here's the table, snaffled up from here.
The chart below summarises a poll from the cyclingforums.com users, most of whom are obviously keen cyclists, albeit amateurs. There is an obvious sweetspot at 300w/75kg that correlates with the table above. I think this is a reasonable FTP target to aim for.