I got the smallest version of the Deep Dimensions (36x36x27), used it as a discus tank - now it's cycling with LR for a FOWLR... Beautiful tank - can't wait to see what you do with it!
I like T5s for several reasons. They get great penetration down to the bottom of the tank and you can mix the multitude of spectrums and manufacturers available to fit your needs or the look you like color wise. I've seen some amazing looking results from T5s. Btw, I'm not sure if you noticed but there is still plenty of room behind that tank... you could have gone bigger lol.