There's a lot to consider when choosing a notebook, from the size to the colour to the material that the cover's made of, and that's just for starters. The page layout will influence how you use your notebook, so matching the page layout with how you want to use your notebook will help you make the most of every page.
Rather than being one 'best' page layout for your notebook, each has its own strengths, and your best bet is to choose the one that lines up with how you plan to use your new notebook. The alternative solution, which is my personal approach, is to have a whole bunch of different notebooks around your house at any given point, so you can easily grab one with the layout that fits your needs.
Dot grid is the most versatile, while Ruled will likely be the most familiar. Plain lets you play by your own rules, and Grid is strict yet supportive. But critically, no matter what page layout you pick up, there aren't actually any rules – if you want to freehand sketch on a grid page, there are no stationery police to knock on your door and arrest you for crimes against paper. Find the one you like best, maybe have a few options, and just enjoy the irreplaceable feeling of pen on paper.