From NBC's Chuck Todd, Mark Murray, and Domenico Montanaro
If it's Friday, it's time for another First Read Top 10 list -- this time our monthly look at what we consider the Top 10 Senate takeovers (i.e., one party losing control of a Senate seat and the other party gaining it). The big mover here is Florida, given the growing chance that Charlie Crist (I) could very well win this race. Caveats: The three-way contest is highly unpredictable, and we still don't know with which party Crist will caucus. But if the GOP nominee, Marco Rubio, loses the race, it's hard to see how that isn't a takeover. The number in parentheses is our ranking from last month.

1. North Dakota (1): John Hoeven (R), come on down.
2. Delaware (2): This race has been quiet, and that only favors Mike Castle (R).
3. Arkansas (3): Passage of Wall Street reform will be a feather in Blanche Lincoln's (D) cap, but she remains the underdog to John Boozman (R).
4. Indiana (4): Brad Ellsworth is up with his first TV ad criticizing lobbyists (see: Coats, Dan). But what is the bigger albatross in Indiana right now: being a lobbyist or being a supporter of the Democratic agenda?
5. Nevada (5): Is Harry Reid (D) vs. Sharron Angle (R) the purest Senate toss-up in the country? The winner might need just 45% (with "None of the above" on the ballot).
6. Pennsylvania (7): If Nevada isn't a pure toss-up, then this race probably is. Joe Sestak's (D) advantage: the Dem registration edge in the state. Pat Toomey's (R): the national environment and the GOP edge in the gubernatorial contest.
7. Florida (unranked): The longer the BP story plays out and the closer the Meek-Greene Dem primary becomes, it's hard to believe how that doesn't help Charlie Crist's indie bid.
8. Illinois (6): We're unsure what's worse -- Alexi Giannoulias' (D) bank woes or Mark Kirk's (R) constant misrepresentations about his record?
9. Washington (10): The GOP now has chances to win in California, Washington, and Wisconsin, but Dino Rossi (R) is probably the strongest of all the Republicans running in these blue states.
10. Ohio (8): Lee Fisher (D) has a serious money disadvantage vs. Rob Portman (R), but does Ted Strickland in the gubernatorial contest push Fisher over the finish line?

The other races we're watching (in order of likely takeover): Colorado, Kentucky, Missouri, Wisconsin, California, New Hampshire, Connecticut. Wow, this competitive Senate field gets bigger and bigger, and you can now add West Virginia. Oh, and this doesn't include Louisiana, which could pop given the intense media scrutiny David Vitter is under these days.