Politico gives the lay of the land 24 hours before thte polls open:

In the waning days of Election 2014, key Senate races that had been razor-close affairs for months have moved toward Republicans — from the open seats of Iowa and Georgia to challenges to incumbents in Arkansas and Alaska. Kentucky appeared to move off the map with Mitch McConnell — poised to replace Harry Reid as majority leader next year — opening a decisive lead.

Democrats still have a path to hold on. Republicans could lose Kansas and Georgia — which would mean they’d need to net eight seats elsewhere instead of six, a tall task. And the GOP needs to achieve a feat that has eluded the party since 1980: toppling more than two sitting senators in a single election.

(POLITICO's 2014 race ratings)

But the national atmosphere, namely President Barack Obama’s unpopularity, may be more than Democrats’ historic investment in turnout can overcome.

Republicans are certain to pick up open seats in the red states of Montana, South Dakota and West Virginia. They need to net three more to get the majority.

Arkansas looks likely to fall to Republican Rep. Tom Cotton. Louisiana is a likely GOP pickup, but it’s expected to go to a December runoff.

Democratic incumbents have an edge in New Hampshire and North Carolina, but polls have tightened in recent weeks.

Two polls from New Hampshire published today show the GOP's Scott Brown more than holding his own against Democratic incumbent Jean Shaheen.  The WMUR-University of New Hanpshire poll gives Shaheen a 1-point lead, while the New England College poll gives Brown a 1-point edge.  If this one is decided before midnight eastern, I will be very surprised.  (If it's decided in the first hour or so for Brown...surf's up!)

More good news for Republicans comes from Colorado, where the Democratic-leaning PPP poll gives Gardner a 3-point lead over Senator Udall.  A win for Republicans in both Iowa and Colorado would almost certainly give them a Senate majority.

In Alaska, GOP candidate Dan Sullivan bests incumbent Dem Senator Begich by one point in another PPP poll.  AT's political correspondent Rich Baehr has pointed out on numerous occassions the problems with polling in Alaska.  It's a Republican state, but unpredictable.  If the race is as close as the polls suggest, we may not know the result for days as results trickle in from some of the most remote places in the U.S.

All in all, cause for optimism, but nothing is guaranteed.