Narrowed my choices down to 2. What's your opinion??

[Scavenger]

Well after discussing in depth with my wife a new reef tank, we came to the following. I can make whatever I want as long as it fits in my 12x15 foot fish/computer room.

After concidering costs, equiptment and the fact that I will probally have to move it in 2 years, I have my choices down to 2. I hope to get some opinions on what some experienced reefers think the pro's and con's are.

Option 1. 48"Lx36"Wx24"H walk around cube in mid floor. All plumbing and wiring down center "hollow/overflow". Initially lit by 6x65 watt pc with MH added later as needed.

Option 2. 64"Lx24"Wx24"H Standard against wall rectangle with 2 corner overflows and corner and midback returns. Lit same as above.

So far, I am pulling for the cube, but that would probally mean giving up my 137 gallon freshwater cube I built last year. All comments and suggestions are welcome. Maybe someone will see a problem I haven't factored in yet.