For Linux users (or Mac OS X users that use the Terminal) who want to pick up a journaling habit:

I set up the following aliases to DRAMATICALLY reduce the "activation energy" for writing a journal entry:

alias jcd='cd <journal directory>'
alias today='jcd; vi `date +%Y-%m-%d`; cd -'
alias yesterday='jcd; vi `date -r \`expr \\\`date +%s\\\` - 86400\` +%Y-%m-%d`; cd -'

So if I want to write a journal entry, I just type 'today' and get started. Note that this also has the secondary benefit of keeping journal entries nicely organized by date.

BTW, I am no writer, but this technique has gotten me to write a decent amount over the years:

$ jcd; cat * | wc -w
92804