Those are a good start-- I've found that HDR gets the coolest and most spectacular results when you use it in situations where there's a big exposure range over the entire image (like a sunset-- the sky is really bright and the foreground is really dark.) In all the situations in those photos the lighting is already pretty even, so the HDR doesn't really have very far to go to compensate for the exposure differences, and they end up losing a lot of contrast.