The most recommended "solid" or durable options from the DPS line are:
If you are filing documents into binders, this is the most "solid" choice because the 20-lb weight ensures the holes won't tear as easily as thinner paper when pages are turned. DPS by Staples 11" x 17" Multipurpose Paper Go to product viewer dialog for this item.
If you find 20-lb paper too thin, "upgrading" to a paper from a similar brand (like HP Premium32 Go to product viewer dialog for this item.