That's a dangerous question to ask! Prepare for a deluge of everything from the mundane to the exclusive to the esoteric. Peterson has a loyal following; half of my pipes are Petersons because of esthetics and price and quality. Nording is a favorite with people who like the Danish tendency for the unusual and for freehands; I have about 4 of these. After Peterson forming the core of my collection, anything goes; Stanwell, Savinelli help fill the gaps for specialties like churchwardens and just plain good pipes. My Savinelli Marron Glace 111 billiard caused me to recruit a British forum member to obtain this pipe because it wasn't available in the US and is an exceptional billiard with a stem that changes with the light and has the largest billiard bowl I've seen from a factory pipe. Then there are the estates for expensive quality pipes that, new, would not be affordable, like my Castello Sea Rock. And so it goes.
And your own collection looks very good, so much of my comments may be superfluous.