I’m coming!!! Oh YEAH!!!

I’m in search for a note-taking software working on both Mac & Windows. In most time I work on my PC; sometimes I carry my ibook around when I need its portable features badly. It is hard to keep my reading notes sync on two computers — that’s why I turn to your guys for help.
Basically I use Microsoft Onenote on Windows. The software rocks — organizing everything well and making my messy notes searchable. The only drawback is so far it is unavailable on Mac. I talked with a friend of mine working in Microsoft China Technology Center about onenote on Mac. Sadly he told me it was not coming. Sigh…
So the following is a list of features I want from the software:
1. Available on Mac & Windows.
2. Sync between two computers. This is an optional function I need. I will manage to figure out how to sync manually if it’s not built-in. Anyway, the world is not perfect, right?
3. Insert URL automatically. When I paste text from a webpage, the URL of it will be added without hassle.
4. Export into Microsoft Word/RTF/HTML/PDF or whatever popular files. I love compatability and hope to switch between different apps.
That’s it! Not too greedy, huh? If it’s open-source or freeware, I will be on the 7th heaven!