Depends on what you want.

Regular trade paperbacks fit perfectly into silver size bags (which are also great for storing story arcs. And of course perfect for silver age comics)

I use mostly those. Easier, and I don't have to scramble for individual issues as much, and it's great protection for my tpbs, from uv etc.

Golden size ones are perfect for hardcovers, like the standard Marvel releases, a normal size hardcover with you know, 6 issues or so.

If you want to store them separately, and they are from the mid 1970's onwards, current size is what you want. Boards are one size anyway.

It really depends on how you prefer to store them.

EDIT: Current size ones are perfect for Voltron and Transformers, other than TF UK issues, obviously.