Personally, I always liked both Shiro and Midori... but my friend and I gave each of the main four colors of Super Bomberman 2 our own little nicknames, so I know them mostly by that...

White Bomber - Colgate Total (We just call him "Colgate" for short ^_^)
Black Bomber - Blackberry
Blue Bomber - Blueberry
Red Bomber - Tomato Paste