Frogspawn and hammer are some of my favorite coral. Be careful with xenia because it can take over your tank pretty quick. You can start with lps if you want. Just make sure water quality is in check before adding anything. Nice thing about coral is they don't add to your bio load unless you feed them.
Yeah, I had xenia in one of my previous attempts-- a 5.5 gallon nano tank. I'm familiar with it's "weed like" properties.