My analysis on them so far, assuming best case scenarios for candidate recruitment:
AL - Safe R (although the nominee might not be Riley, let's just hope it's not Roy Moore!)
AK - Safe R unfortunately
AZ - NCF
AR - NCF (I hope Clark runs)
CA - Leans R unfortunately
CO - NCF
CT - Leans D (although better for Republicans now that they don't have that albatross Rowland around anymore)
FL - NCF
GA - Leans R
HI - NCF
ID - Safe R
IL - Leans D
IA - Leans D (if Vilsack runs again. Is he term limited?)
KS - NCF
ME - Leans D, unless Snowe runs like rumored
MD - NCF
MA - Leans D if the Democrats get a half decent candidate
MI - Safe D
MN - NCF (and I will be working extra time to remove my state of the disgusting vile scumbag that is Tim Pawlenty)
NE - Safe R
NV - NCF
NH - Really impossible to tell, depends on how popular Lynch gets
NM - Safe D
NY - Leans D
OH - NCF
OK - NCF
OR - Leans D
PA - probably better not to go here, discuss this in the million other threads on it
RI - same as MA, Leans D with a half decent candidate
SC - Safe R
SD - Safe R
TN - Leans D (although if Frist has half a brain he'll realize he has no chance of being president and would run for this instead, but I bet he won't)
TX - Safe R
VT - Safe R unless Dean decides to make a comeback
WI - NCF
WY - NCF
My quibbles:
CA - If Ahnold runs again, Ahnold will win. This is more than lean R.
CT - They like to elect R's to state level offices. It'll depend on the candidate the Dems put up. Right now, leans R.
MA - They like to elect R's to the governor. Tossup unless a good D candidate appears.
TN - If Breseden runs again (term-limits?), he would win easily.