rock
Happy New year guys! I meant to comment on this thread before but didn't have time.
I think #2 is the best but there are still better things you could do with it. Its a tough landscaping job in your case because you have a bunch of frags and its harder to make that look "natural". If you can do it, I would try making a smaller cave and then a small island off to the right or left. Or small ledges and an island.
For me when I'm aquascaping I prefer not to repeat the same pattern. It looks more natural if you have a cave, island, and pillar or something like that. It really depends on the type of rock you have to work with as well.
Its not very popular with most reefers but I think haitian lettuce rock is some of the best to work with. Its very porous/light and is very natural looking in a reef tank. It also has a lot of ledges and hollow spots throughout so it can hold a lot of corals but won't look like a table like some rock. I used kaelini in a big tank, it wasn't my choice. I found that rock to be very dense/heavy, it also has very little caves or indentations throughout the rock so it is very hard to place corals on it without epoxying everything down. I've had poor success with epoxy in the past so I try to get nice rock shapes with lots of nooks/crannies.
Another thing I do when aquascaping is place all the rock I have to work with on the floor so I can look at it. This makes it easier to try out in your mind how different groups of rock are going to look together.
I prefer to use a bit of tonga branch on the bottom as supports to the main rock work. I sink some pieces halfway in the sand and place the haitian rock on top of it.
This also helps the sandbed to do its job more efficently because if you let large rocks cover the sand that blocks your sand's ability to cycle things properly. Most tanks I aquascape are only 30-50% filled with rock, less is definately more.
I try to keep in mind what kind of fish and corals I'm going to put in and aquascape to their needs. Filling a tank to the top with rock is cruel to your fish because they have no where to swim and usually very few caves to travel in and out of.
If you are doing a one sided tank and using the back glass as a rest its good to try and make hollow spots/caves in the back so your fish have lots of places to explore. We are already taking them out of their environment into a much smaller setting so its important to give them plenty to do so they don't get bored.
A lot of people forget to give their corals room to grow and stack their rock high. In your case I would suggest gluing down some of your frags to the rock so they start to spread and look like they're part of the rock. Also I would place some of your larger corals in with your smaller frags to give it a more random look.
Good aquascaping is a lot like nice art work, you want to try to create movement and not let the eye rest on one focal point. Another look I like is the more contemporary empty look with a few show-size corals. In all great tanks its the corals that make them standout, not the rockwork. A good thing to do is look at a lot of other tank pictures and incorporate the best elements of other people's designs into your own.