Some two hours before they should officially announce it, here's my prediction for this year's Economics Nobel:
The 2008 Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel goes to Oliver Hart, Bengt Holmstrom and Oliver Williamson for their contributions to the theory of the firm.
Now, this is not very original, since I predicted the same, obviously without success, last year :-). Let's see. It's either this or the macro side (Barro et al). Finance rather unlikely this year (Fama, French etc), though obviously deserved in the very near future.
PS. Steven Levitt seems to have spotted a proxy for who (among potential candidates) thinks will get the Economics Nobel, i.e. people who get a haircut shortly before the announcement :-).