1) Evernote: I've had my ups and downs with this software. Until its recent UI revamp, I really hated using Evernote to do anything. However, now that they've gotten most of the bugs worked out, it's actually quite nice having the ability to sync up with my PC, Mac, and iPhone to have a ubiquitous, ongoing notepad of things.
2) Notepad + Dropbox: This was what I was using before I switched over to Evernote. I had a folder on my Dropbox called "Notes" and I just created *.txt files and did my notes there. It would sync to both my PC, Mac, and iPhone and I could easily organize notes within a folder structure.
3) Thumbdrive + Folder Syncing Software: I guess this is where my really important stuff goes - on my security locked USB drive. I used some folder syncing software for a while, but none of them really worked out, so I kind of just work off my thumbdrive directly when I need to. However, if anyone knows of a great syncing solution that has a lovely UI and is non-obtrusive, I'd love to hear it!
Got a digital note system that you'd like to share with your fellow readers? Let us know your process!