More height or more depth?

Definitely dept over height. Its so much easier maintenance wise and makes for a much easier aquascape.

 

I have a 30" tall 100 gallon. My stand is also a bit higher than average. When I was setting it up, I needed to use a step ladder to move my LR at the bottom. However, with the exception of having to take apart half my aquascape in the fall to catch a starfishing munching crab, there's nothing that I haven't been able to accomplish in my tank using my aqua tongs.

It all comes down to personal preference, and depends on how much you like to tinker with your tank. If you tinker a lot, then a taller tank will be slightly more inconvienient, but not to the extent that some people make it out to be. I have tall ceilings in my house, so the taller tank looks perfect and it's well worth the bit of extra effort.

 

I just started filling my 150 and I do need a step stool to place the rock and get into the tank. The base is also tall. 32" making the top of the tank 62". I hate bending down to look in a tank. Going to 24" deep after having 18" deep with my 90g is a big improvement.