So I've made my tentative predictions for the results tomorrow.  Let's dig into the Senate a little bit more.
My basic assumption here is that Republicans are likely to hold all open   GOP seats and are (barring something very strange) clear favorites to   get at least 4 Democrat seats (AR, IN, ND, and WI).
And then the  toss-ups.  What follows below is my ranking of toss-ups, from what I  guess to be most likely to switch to least likely.  I emphasize that  this order is very, very tentative, and I would in no way be surprised  if some of the seats higher up the list stayed Democrat while lower  seats switched parties.
The Good Chances
Pennsylvania
Pat  Toomey has led throughout most of the polling cycle, even if Joe Sestak  has closed the gap a little recently.  Sestak has a reputation as a  strong closer, but I don't think he's got the numbers.  Sestak is a  pretty far-left Democrat, who could have won in 2006 or even 2008  (maybe), but Pennsylvania doesn't seem like his territory in 2010.
Illinois
Mark  Kirk has had a very slim lead over Alexi Giannoulias for months now.   Giannoulias has been dogged by ethical questions throughout this  campaign.  Neither candidate has ever really cracked the high 40s in  polling, so there could be a surprise here, but it looks like Kirk has  the edge.
Nevada
Sharron  Angle has struggled against Harry Reid.  Neither candidate seems  particularly popular in Nevada, but Angle seems to be pulling ahead in  the final days of the campaign.  With Tuesday approaching, Nevada voters  don't seem comfortable with pulling the lever for an increasingly  left-wing Reid and for the Obama agenda.
Colorado
Republican  Ken Buck has had a few difficulties on the campaign trail, but Democrat  Michael Bennet is facing a very hostile political environment.  A  divisive governor's race (with a failed GOP candidate and an empowered  Tom Tancredo) may pull down Buck.  But polling gives Buck an edge, and  he seems to be pulling away from Bennet.
The Unknowns
West Virginia
This  state is puzzling.  It has a radical antipathy to Barack Obama and his  agenda.  And yet it may be on the verge of sending a Democrat into the  Senate.  Democratic Governor Joe Manchin is personally very popular and  separated himself from the administration on cap-and-trade very early  on.  But now Manchin has much more explicitly distanced himself from the  White House, including reversing some of his former positions.  For  example, in the heat of the health-care battle, Manchin supported  Obamacare; now, in the heat of the campaign, he has denounced that  measure. Republican John Raese had successfully attached Manchin to the  Democratic agenda in the early fall, but now Manchin seems to have  successfully danced away from his old allies and has regained his lead  in the polls.  I'm still somewhat bullish for Republicans in this race,  though.  Will WV voters really go into the voting booth on Tuesday and  not fear that Manchin will, once in office, cast his vote for  "progressive" plans?  I think those reservations could sway some  voters---Tuesday will tell if they sway enough.
Washington
Patty  Murray is vulnerable, and Dino Rossi has run a good campaign.  Coming  up on Tuesday, this race is about as close as it can get.  A wave could  definitely propel Rossi over the top.
The Long Shots
Connecticut
It seemed in early October that Linda McMahon was narrowing the gap  against Democrat Richard Blumenthal, but the rest of October saw  Blumenthal expand his lead.  A Republican win could happen, and there  are a number of close House races, which could help McMahon.
California
This race seems within five points, but those are a long five points.   Under perfect storm conditions, Carly Fiorina could pull off a win over  Sen. Barbara Boxer.
Delaware
This state is so small that a surprise could happen.  But make no mistake: it would be a SURPRISE.  The RCP average of polls  has shown little real movement in the race for almost six weeks, and  the picture isn't a pretty one for Christine O'Donnell---a 10+-point  Coons lead.  O'Donnell did surprise some pundits with her victory over  Mike Castle in the Republican primary, but polls taken prior to the race  did show her leading Castle.  That kind of evidence is lacking this  time around.  Maybe her 30-minute epic commercial airing today and tomorrow will help her beat Coons.
