Agreed. Although many one-liners are irrelevant to theme and setting, the best ones are very relative to it.
"Ouch, right in the tentacles!" wouldn't work unless you've got a giant alien octopus character, for a lame example.
In the case of Duke Nukem, they ripped off the epic Evil Dead movie series a fair bit for their one-liners. You might consider similar inspirations. The Boondock Saints also comes to mind for a good source of inspiration.
I would provide some of the Boondock quotes, but well... I don't want to swear here unless I really have to.
