I figure readership here and at the Monkey Cage must have a pretty good overlap, but just in case: be sure to check out John Sides' nice post on the futility of self-financing, based on research by Jennifer Steen. Key point: a dollar of self-funded spending buys fewer votes than does a dollar of donated funding.
To give you a bit of value-added beyond what John said...something to keep in mind generally about elections is that the press is apt to significantly overstate the importance of money in politics. That doesn't mean that campaign spending is useless, by any means. But we can say two things about it: first, that other factors (such as partisan identification) are far more important than money; and, second, that money raised and spent is usually a consequence of other things (strong candidates, weak incumbents, national partisan tides), so if we understand those things, we don't need to account for (some of) the effects of money. Moreover, and alas for Meg Whitman, to the extent it matters money also has diminishing returns (which makes sense...money can clearly buy name recognition, and people don't like voting for people they've never heard of, but it's a lot harder to believe that the 7th or 8th thing you hear about a candidate really sinks in and changes your vote). You've already seen, and you'll see a lot more, about floods of money unleashed by the Citizens United decision, but keep in mind that it almost certainly matters only around the margins. Of course, "around the margins" could determine control of Congress, and we'll have to wait until after the election for studies about the actual effects of money this time around -- and I do think that it's good reporting to let us know who is financing campaigns whether or not it matters to election outcomes. Still, just keep in mind that money is only a relatively small piece of what's going on.