65lb Matte - thin cardstock but not as thin as copy paper.  We use this cardstock for items going into frames.
100lb Matte - thicker than the 65lb Matte and sturdy enough for adding to small stands.  We use for our menus, place cards and stationery
110lb Matte - a very nice sturdy cardstock.  We use for our invitations and menus.
107lb Metallic - a very nice sturdy cardstock that also has a nice soft shimmer on both sides