My MBP is definitely name "MacBook Pro"
Now on the MBP under shared, like I said I see iMac and iMac (2). If I try to connect to iMac, I cannot. I can only connect to iMac (2), which is what actually shows up as the computer name ON my iMac. It used to be simple. On my iMac it was named iMac, and when on MBP, under shared, I only saw iMac and could connect to it no problems. Now for some reason, I see two.
I will test it like you said, power off the iMac and see what is under shared on the MBP. Good idea.
As for anything else on the network, I don't have anything. But, the only remotely possible thing I can think of is a few weeks ago, around when this started happening, my friend came over and fired up his brand new MBP. He connected to my network to get internet and that was it. But if anything, that default name would be MacBook Pro right? I can't see how a brand new MBP could have a name of iMac. Is there any other way a second MBP could have screwed this up?