I would recommend staying away from the more common Caulerpa's, etc... They tend to be a PIA to clean up, and while they do grow well, aren't always liked by the fish, and pose other problems (like turning to mush every so often if you're not careful)
I've had absolute fantastic luck with "Brillo Pad Algae". It's been tentatively ID'd by my group of friends as Chetomorpha, I got mine from Chucker, who got his from a friend, who got theirs from Inland Aquatics... It does not go sexual, it does not attach to the rocks, and my tang loves it! It looks like green Angel Hair Pasta, and grows in tight wad's like a brillo pad (hence the common name).
The Tang Heaven Red I've only had marginal success growing, and it did not last long (tho I did like having it, and the Tangs did go nuts). The Tang Heaven Green was even harder for me to grow. I think both of those algae's like slightly colder water than what most of us keep our tanks at.
However if you've got it setup and haven't gotten past running the plumbing... now would be a great time to throw in a boatload of Sand. Seed it with some LS, get a refugium kit from Inland Aquatics or somewhere, or see if you can't buy one off someone on this board. The Bugs are the big part of a refugium, and the sooner you get them going the better off they'll be.
- Mac