What about the most long lasting brand and/or flavour of gum? As a rule, I find mint flavours (strong, not spearmint, although I prefer the latter) last longer than fruity ones. edit: to clarify, I mean which retains it's flavour best as you chew it, i.e. after 30 min of chewing, you can still taste the flavour.
Elixir? Solstice? LUSH?! There's no way I'm chewing gum that's taken it's name from an inflatable sex doll.