I am pretty low-key when it comes to journaling. I use the mass-market journals found in bookstores and I am a hardcore user of Pilot Better Ball Point with a fine tip pens. Seriously. There's only one store in my city that I know sells them and I go there specifically for these pens. They are not high-quality pens but I've been using them since I was a kid and I love them.

As for as decorations go, I love stickers. I avoid the puffy/3-d ones scrapbookers tend to use, but there are plenty of flat stickers out there that won't bulk up your journal.