Originally Posted by SteelSD
From what I've read, either "I'm just the man for the job." or "I'll take you to your grave." would be reasonable interpretations. But considering that Holliday's next words were "That's just my game.", I'd suggest that "I'm just the man for the job, that's just my game." would likely be the best interpretation as "I'll take you to your grave." probably wouldn't have needed a follow-up after Holliday's prior Latin phrase that can be translated as "Rest in Peace".
Holliday repeats "I'm your huckleberry." prior to the final standoff with Ringo and then said, "Why, Johnny Ringo, you look like somebody just walked over your grave." At this point, I have to go with "I'm just the man for the job." or "I'm just the man you're looking for." as being the most likely meaning, considering that an announcement of "I'll take you to your grave." likely wouldn't be followed up with a declaration that someone just walked over it.
Especially since (and this may not have any bearing but it might) Ringo would have been looking for Wyatt at the time.