I'd like brewsmith, but I don't have the money to buy it, I'm using brewzor for the phone, and I jot things down on a paper notepad, as well as some random blog site.
Whatever method you use, make sure you back it up. There was a post earlier about someone who had a fright when his binder logs were put somewhere.
I've mentioned it before, working in a datastorage industry, that you want multiple backups. The company I work for has multiple data locations and daily backups for at least a month. Paper(binders), electronic(scanned, word doc, pdf, brewsmith), online(blog, email, google docs), or online backup (mozy, carbonite)
The issue with physical is destruction and physical misplacement, electronic (on only one computer) is a possible computer failure losing data.
I like multiple online sites. Don't trust one email location either (yes, you can email things to yourself like recipies or backed up brewsmith files) but recently, hotmail had lost some people's email, so have a hotmail and a gmail, a wordpress, a blogspot.
So have some redundancy.
Beer is important!