Ive actually been looking at a scanner, I am thinking of either geting a fujitsu scansnap or a canon pixma and then getting rid of binders and notebooks entirely, it would also be nice to just scan all my mail/bills/receipts/manuals/etc. and have everything be in a digital format.
This is what I have done. I have the ScanSnap S510 hooked up to my windows/linux desktop, but they do make a mac version (now). It made my life so much easier. I didn't go this route until my last year in undergrad, but it enabled me to have the best performance of my academic career with 17 credit hours and working 10-20 hours/week. Now I'm using it for receipts, mail, grad school work, and everything else that ends up trapped on paper. It frees up a lot of my mind and nothing is ever lost. Plus, now I can realistically file a Schedule A next year with my taxes.
For your original question, I just thought I'd interject that Textwrangler works fine for me for in-class notes. My portable is a mac, and my desktop runs both windows and linux. I haven't found anything more cross-platform than plain text. I'm in Computer Science now, so diagrams are far and few between...and when they come up, I get to draw them with hyphens and pipes! When I'm taking notes from a textbook I'm reading, I use FreeMind...which is just as cross-platform, but displays things in a mindmap.
I have more things digital than is arguably practical; I'm a total convert to paperless information. One thing to keep in mind is backup solutions. I read something a long time ago from a place I don't remember: "If your data doesn't exist in three places, it doesn't exist."
I have MobileMe and a USB drive on my keyring that I use to keep multiple copies of current things. These current things are synchronized daily to four places quite easily thanks to MobileMe and Microsoft's SyncToy 2.0. When something isn't relevant anymore, like all the stuff I had from high school that I scanned (in a snap!), I archive it and leave it on everything but the keyring. When and if MobileMe gets full, I plan to take it off there and burn it to two discs. I'd keep one at my place and send one to my parents. Some would say this is overkill, and some would say it's not enough.
Excellent thread, by the way. I've picked up a few tips I'm going to try next semester. Thanks to all for your contributions.
For those who are against taking the portable to class because of distractions on the internet, I had this problem too at first. I got rid of the time wasted by opening up stickies and always having one note in plain view. On that note: What I have paid for school so far; how much I owe for school so far; what I made at my last job hourly; how many hours it would take to pay back what I owe. It was a rather sobering experience for me.