Waterman Serenity Blue (formerly known as Florida Blue): A standard blue ink of medium saturation, Waterman Serenity Blue will not wow, like more showy blues, but it is a workhorse that has stood the test of time. Washable, not water-resistant.
An everyday ink? Yes.
(Here begins an occasional exercise, the brief review. I got the idea from a friend who thinks that most reviews could be four sentences or less. While I naturally gravitate to Dickensian length, I thought it would be fun to try.)