Museo is a serif font. It goes well with Museo Sans, Open Sans, Museo Slab and Quicksand. If you're thinking about using Museo then try 48px for headers. Give 15px a shot for content.
People commonly tag it as big, elegant, simple, bold, clean, slab serif, fashion, sans serif, blog and serif. You can get it from Font Squirrel, Fonts.com, Fontspring, MyFonts and Typekit.