About a month ago I picked up a set of two Maruman Mnemosyne A4 gridded notebooks, curious to see how they worked for wireframing websites.
In the past month I've been impressed with how well the Mnemosyne notebook has performed, so I shot a brief review video of the notebook to share with you:
I love the smooth, calendared paper in the book, because it holds pencil so well. Even soft pencil sketches seem to hold in place without smearing like other books that have paper with texture or tooth on them.
The size is also nice, as A4 (210 × 297 mm) provides a little more vertical height than US Letter sized 8.5" x 11" sheets of paper. This gives that little extra on the top and bottom, which works well for site design, which tends to be more vertical.
Lastly, the light gray grid is strong enough to be seen but light enough not to get in the way. The grid is also relatively easy to knock out in Photoshop, convenient for making your wireframe sketches cleaner for presentations.
Maruman Mnemosyne notebooks can be bought at JetPens.com in a set of 2 for $32. They're not the cheapest notebook, but the balance of paper quality, size and grid tonality make them worth the extra cost to me.