Not the search business.
MSN's search results are horrible and their focus is fragmented from software to video games to search. Google has only one focus to catalog as much of the world's data in the most accurate and easy to use way possible.
A lot can be said for laser focus when going up against a bigger rival.
Google generates over 1 billion in revenue per quarter and according to their most recent financial statements have a cash value of $7.6 billion dollars. So even if they cut a check for a cool Billion it will be made up in less than a year.
We all think AOL stinks and it does but you can't ignore a user base of their size and when many of their subscribers do jump ship what search engine will they be familiar with and continue to use?
It won't be MSN.
Why not try to catch legions of "newbies" and techno phobes early and get them to trust and be loyal to the Google brand for the long haul?
If they can do this their market share will only grow while Microsoft's dips.
It's a battle for market share and long term supremacy. Maybe to Google that is worth a billion.