I guess Sunbeam would be closer in the literal sense.. but I feel Sunshine is closer in the "bright and happy" connotation.

The Trigun anime doesn't kick off until like.. halfway through the series, at Episode 12 or so. And even then the manga is better. Er. not that I ever got any further than Trigun Maximum #4. (I couldn't afford more for a while and then I fell head over heels for some new fandom)