moving dilemma

So, I may be moving out to a college dorm this fall. I can't take my tanks (115 & 37 g, unplanted) with me. And asking (and relying on) someone to care for them is out of the question. So I will give the fish away, but I will not give/sell the tanks. Here is my question:

Should I drain the tanks and let them sit there until I return? (the following summer, I suppose)

Or could I unplug everything except maybe the filters?
Would the water get "nasty" after some time?

Even though it is a waste of electricity, I figure a filled tank wouldn't be as un-attractive as an empty tank. Any thoughts or other ideas and opinions would be appreciated.

Those are all valid arguements that I haven't thought of. Thank you. This decision will be harder than I thought...

Let's say I did a 100% water change before I leave to get most of the organics (as OG stated) out. And assuming I could get someone to top off every so often (as LT stated), and doing another 100% when I return.

Would I be ok to leave them running?

Would I still have stench and buildup problems?

I don't have any storage space, and I'm definately not going to pay for storage. I would rather leave them where they are, since they will go right back to the same place when I return. And again, I think an empty tank will be more of an eye-sore than a running tank.

Maybe a better question would be:

How can I keep a tank running without fish, for an extended period of time? How can I reduce any repulsive odor, and any type of buildup that will develop?

Thank you, again.

BTW, somebody will be living in the house, but I can't ask them to do weekly water changes on the 115. So, when I said I will be leaving, I didn't mean to imply that the tanks will be completely unattended. Sorry if I mislead you.

That sounds reasonable, thanks.