Overall I like the purple and blue variations for pansies and roses, they're very pretty! I find these colors soothing and relaxing to look at when walking through my village.
Definetly roses, especially in NL. They look so good, and the colour range they come in is the widest, so there's so many varieties you can choose from.
I picked carnations but it depends on the colour for me. I love white and pink carnations, pink lillies, blue roses, pink cosmos. Jacobs ladders are probably my all time favorite though, but I don't think they count. The only flower type that I don't like any colour of are pansies. (that wording is really bad, but i'm saying I don't like pansies at all)