"OK, tried the "phantom" center yesterday, and I hate to say this, but it didn't sound good at all. Very hollow sounding, I tried some other setting changes, but just turning the center on again was a huge improvement."
OK, for the record, to all the newbies, novices, and otherwise lesser experienced among us, the reality here is likely that there are many variables that effect the performance and results of a system. Simply changing one variable does not tell the whole story. For instance, there's a very very good possibility, in this situation, that the mains are likely located in a position in the room - relative to the seating area(s) - where there's a hole in the frequency response of the main left/right speaker setup. Also, there may be crossover issues, phase, etc.
Acoustics and system set up play such a huge part in the equation, that it all must be taken in context, when evalutating, trouble-shooting, and tweaking a system.
I would venture that there likely was not any care in setting up most of the system in regards to system response, initially here. So, to assume from the above statement that no center here is "not workable", is presumptuous. For informational purposes, anyway.
It is very very workable to PROPERLY setup a 2.0 or 2.1 system (allthough this is usually more effective dynamically, overall), sans the center. Not to say you should go without a center. But it can be done well, if properly considered and executed.
Thought I'd put my two cents in here...