for nutrient export, you want something that's fast growing such as Chaetomorpha (mentioned) or some of the faster-growing Caulerpa species (e.g., C. taxifolia, C. racemosa, C. prolifera). Cheato isn't such a great looker (looks like a green brill-o pad), so most folks relegate it to their sumps.
for interesting looks you might consider Codium, Sargassum, Botryocladia, Galaxia, Halimeda, Octoides, etc.
we use live macro in most of our setups and they look nice and really help with water quality.
HTH