Three ideas keep me from dropping the dream...
1. You can't just say Google is the 800lb gorilla, so you can never challenge them. I remember when Yahoo! was that gorilla and Google came from nowhere.
2. Again, the MP3 player argument. Apple could make a better Yahoo! or Google IMHO.
3. Name brand recognition. Apple did it's own browser. It's taken about 5 years to get to 7% market share. Yet they still try. .Mac still virtually unknown to non-mac folks (I still can't iChat with anyone but Mac people

). But if Apple bought a name, which is kinda new territory for them, well that changes everything.
And three ideas keep me from dreaming deeper...
1. Bad investment
2. Bad investment
3. Bad investment
The value in that name is high, but not $44B
So the simple question to ask yourself is, would iYahoo! sell more iMacs, iPhones, iPods, etc.?