I have registered a number of cook domains with various endings. I would guess the .com versions would be worth quite a bit but I think this is likely to change over time.
I see many different extentions in the serps so I don't think the main search engines have any preference now.
There may be some bleeding of traffic but the lion's share appears to default to .com and likely will continue to do so. Much of what's been built up has been built under .com, so it's likely that the "first mover effect" will be longstanding.
YMMV.
