Welcome to Scrapbook.com! I think that it just depends on what you want. There are 12x12 albums that don't need the outside decorated like the We R Memory Keepers 12x12 albums, and the KMA 12x12 albums. Or if you want to decorate the outside, there are albums such as the American Crafts albums.
As far as page protectors, you can just buy the same brand page protectors, or if you still aren't sure which ones to buy, you can email our customer service by going here: http://support.scrapbook.com/
There is a difference between a photo album and a regular "layout holding" album. A photo album usually just holds your individual pictures. They are more used for when you organize your pictures and need a place to safely store them until you can scrap them, etc. A "layout holding" album is used more for keeping your pages safe after you have made them.
Right now, Scrapbook.com has a deal going on, where you can get 10% off of your order. To see more about this, you can follow this link: http://www.scrapbook.com/blog/view/151903.html
I hope this helps!