If you want some awesome HD vids of your tank, then you better have some frags in there to look at :D
I'd buy small frags, esp since you have a tiny tank. Seriously, buying a single head of a duncan or a 3-headed candycane, or a frag of zoas, or a birdsnest frag, etc., will be totally fine in your tank and will make it look full in no time. If you had a 90g tank then you might want to think about buying large colonies, but with a small tank I wouldn't buy anything but small frags. And also remember that a lot of the LPS corals can be semi- or agressive - meaning they need several inches of room between themselves and other corals otherwise they will sting each other to death. This is easy to accomplish in a large tank, but much harder in a small tank, so something to keep in mind when you choose your corals, their size, and their placement (and make sure to leave room for them to grow).
As everyone else has said it depends so much on water quality, lighting, flow, stability of parameters (as you know, I've lost some of my corals due to temp swings by a few degrees, or salinity increases from a small water change). Tiny tanks are hard to regulate (as you know), and I'd recommend staying away from SPS frags for that reason - they just aren't as forgiving. Some brain species are also less forgiving Get hardy corals, and corals that aren't going to take over - xenia is nice, but will take over your tiny tank in no time. Instead think about a different type of spreading polyp like pipe organ that won't grow off the rock you put it on or blue cloves that will fill in space between other corals without drowning them out. And finally, expect to lose some frags - for whatever reason, there are just some corals that won't do well - I've lost some zoas, bought another batch of the exact same thing and the second one thrives while the first melted away. It can be pretty hit or miss - best thing you can do is just try to really buy healthy corals, dip everything in coral rx, and sit back and watch them grow - a few months from now you'll start to see changes!
Anyhow, just wanted to give you some food for thought!
