Harli and Jungle, my two favorites!
I agree, high quality of either one should give you what you are looking for, even a really nice quality pastel will have the look you're wanting. In general, jungles may have a higher contrast with a lighter base creme color on top with the thick black borders around the tail saddles giving a good contrast. Harlequin lines may give a really great base color saturation (oranges and pinks all over) along with some neat patterns as well. So for contrast, I'd go jungle and for color, I'd go harli.
I'll try to get a shot of a jungle with a normal harlequin (most of the ones I kept are hypo harlis) to add to this thread. Although mine are nice, I wouldn't say they are 'the best of the best' but to try to illustrate the differences I'm mentioning.