The only betta I've ever dreamed of before buying was my current white HM boy (I have never seen another shop in my city carrying HMs!). After Apollo died, I kept thinking "A white HM would look so beautiful in this tank". Then I saw my boy. :) He's not a true white and has some sort of butterfly marking, but he's gorgeous.
I'll just buy the next betta I fall in love with, I suppose. :) But I would love to breed turquoise butterfly halfmoons. :) And copper plakats.