THIS is the journal I usually use -- it has always been my favorite. You can find them at most art stores or online, this is just where I got mine last. They used to be called Field Drawing Book now they are called Art Book. Either way, I have been using the 7"x10" for my art journals since I started art journaling in 2004. Wow, 10 years ago! But I only have 4 or 5 journals as I am not a real frequent journaler and sometimes I use other books. Well I do a lot for a while then stop and start up again months later -- at least that has been my past experience. It is one of my intentions now to be more regular with journaling.
Paper works for painting as well as drawing/sketching. Mine says it is 90# paper even though the Dick Block info says 80#. Maybe I had an older one with thicker paper, who knows?