Later today I will find out what my Senate projection says are the four closest Senate races are, but for now, here are what I think those four currently are, and the latest polling on each:
Illinois between Democrat Alexi Giannoulias and Republican Mark Kirk, Nevada between Republican Sharron Angle and Democrat Harry Reid, Washington between Democrat Patty Murray and Republican Dino Rossi, and West Virginia between Republican John Raese and Democrat Joe Manchin.
Illinois: Rasmussen Reports has a new poll today on the Illinois Senate race, and Giannoulias takes the tiniest of leads: 44-43, MoE 4. This comes one week after the poll had Kirk+4. This is an unusual race in that both candidates are relatively unpopular, but whatever the reason, neither one seems capable of sustaining a significant lead.
Nevada: The inspiration for today's post, we've got two very similar but opposite results: Fox News/POR has the race at Angle 49-Reid 47 (MoE 3), While PPP has the race at angle 45-Reid 47 (MoE 4.4). Average the two using my formulas and the advantage is slightly to Angle, but Reid's taken 3 of the last 7 polls, so it's not exactly a runaway.
Washington: This race has been swingy, but I'd personally characterize it in the neighborhood of the new Fox/POR poll: Rossi 47-Murray 46 (MoE 3) gives Rossi a very small lead.
West Virginia: A late entry this cycle, given that nobody knew that Byrd was going to die, and the in-state debate on whether a special election would be held, but it's clearly a real race. Raese was starting to run away with the Real Clear Politics chart, rattling off four straight after Manchin's four straight, but PPP's newest at 48-45 (MoE 2.8) in Manchin's favor brings that back closer to even. Of the four I think this one is the least likely to end even, but Manchin is so popular in state and is showing himself willing to throw his party under the bus to get elected. Obama's hugely unpopular in state, so that matters.
So if you want to give money to Senate candidates, I personally would recommend these four, and especially to [Rossi, oops! That's what I get for quickly adding cheerleading to a crosspost from UV!] and Angle as the highest leverage candidates: close races in smaller media markets.