Off hand, I'd say the 80's Gatchaman dub "G-Force". They kept the original content: (more or less), the death overtones, Jun's panty shots, and didn't dumb you down. Granted there was the Harlequin type names but you'd forget that when you saw the maturity of the dub.
Second place, Pokemon. Because they did a respectable job for the most part, just removing the Japanese ness of the early seasons and the odd edicts of the later seasons (the panned in look and the badge case).
Third place: Yu-Gi-Oh, I love the English cast and they are...kinda respectful but then Yu-Gi-Oh ramps up the content so 4Kids has to counter that in their own weird way. If they could keep the English cast and leave the content alone, it would be heaven.
Same for DIC's Sailor Moon, I love the voice cast (particularly end of R), didn't like everything else. Heh.