Most any spiral bound notebook is going to lie nice and flat. The question becomes how large is the spiral binding (how many pages) and how much of an impediment does it become when your hand hits it and you have to adjust to go up and over. For this I have to say the Apica side bound are great as the wire binding is low profile. My Rhodia and Black n' Red notebooks have a much larger binding which gets to be annoying. It put me into a temporary bind as I really like the Black n' Red paper quality and notebook. It's cheaper and has better paper than Rhodia. I recently bought one of the hardcover case bound Black n' Red notebooks and thus far I really like it. It may not lay exactly flat on the table when open anywhere but straight down the middle, but when it's open it is flat from page to page.
Black n' Red Spiral vs. Apica Spiral - The Black n' Red binding is around 17mm while the Apica binding is just over 11mm, so ~1/4" difference.
http://i191.photobucket.com/albums/z...psztswqo6d.jpg
Black n' Red Spiral vs. Rhodia Spiral vs. Black n' Red case - Rhodia binding is around 16mm.
http://i191.photobucket.com/albums/z...psuy7lwiu4.jpg