My room is a myriad of notebooks. Some of them have a dedicated purpose of topic. I have my jewelry business notebooks: one for business matters, the other for designs and patterns. I have three writing notebooks: one that lives in my backpack and contains sections of various fan fictions, one that lives beside my bed and contains all manner of random writings, and a third that lives on a random shelf that contains the beginnings and notes on my graphic novel script.
For me, these topical notebooks work, but some people prefer to just keep everything in one place. A blank journal serves this purpose well. You can find them in just about any format you want: lined, unlined, half lined and half unlined, grid paper, half lined half grid paper. You name it, you can probably find a blank journal to match your style.
It amuses me, though, that things like my Flavia journals I’m so fond of and this new Idea Book exist. Despite the fact, I do love and use my Flavia journals, I think I’m capapble of recording inspirational quotes, anecdotes, and activities on my own, and can tailor them to my own eclectic tastes.
Again, though, I think this is just another case of doing what works best for you.