.. is due for replacement.

bets are being taken for the name of it's successor

naming possibilities include:

D90s
D90x
D90.2
D90(a).. (where a = any other alphanumerical prefix)
D9b ... (where b = any positive integer, such as 1, 2, etc.. eg, D91, D92.. etc)
D100!! ..(LOL!)

realistically apart from the s and x prefix, they have nowhere else to go!

NOTE: with Nikon's previous history of body replacement every two years, and the fact that the D90 was announced in Aug 2008.. I'm only speculating that it's due for an imminent update.
Considering that the D300s is still active in the line up, a new sensor is 99.9% guaranteed NOT to be a feature, so the odds on the D90s name are something like 0.50c .. all other names are paying more like $1,000,000 ... just be sure to send me your money in small denominations, non successive serial numbers, and neatly bundled into brown paper bags!

BTW! I think the odds on a Collingwood flag for '10 have dramatically shortened in the past 24hours!