Biggest Tank For Me

[this is me]

A cube would let you be more creative on aquascaping but 18" wide would be enough.
My vote is also for the cube (24x24xXX) or (30x30xXX)
I wonder how well a 250de will lit up a 36x36xXX if it lit up the 58gal(36x18x21) nicely.

 

[~Flighty~]

I vote for cube too, but buy my 58 as a temporary upgrade while you wait