Well Natsuiro no Sunadokei *is* technically a harem, but you don't really notice it, because the main character only loves one girl. It's all about him trying to save the one girl he loves.
And the other two I said previously aren't Harem. Chobits is really good for romance, give it a try. (Comedy as well)
I havn't seen Lamune though, so I can't compare.
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