It looks like you have a great location! A general comment about 30" deep tanks is that unless you're really tall and lanky, you're not going to be able to touch the bottom of the tank without getting your armpit wet, and you certainly won't be able to touch the sand at the front of the tank once the rocks are in when you only have access from one side. You will definitely have to learn to be good at using tongs.
I do have to say though, that a 30" tall viewing pane is soooo much more pleasing than a 24" tall viewing pane. Imo, if you're going 30" tall, I'd also go 30" wide. For saltwater tanks, it is so much easier to aquascape the rocks when the height and width are either the same or the width is greater than the height.
So...what do you have planned for equipment? What type of corals?