Within the gaming context, (where we have control over what we see most of the time), I vote strongly for "pass behind" the bezel.
Our brains are very used to having partially obstructed vision. Think of the pillars in a car between windscreen and side window, or blinds/pillars in a house window. If we want to see something that's blocked, we just move our head without even thinking about it.
Within the gaming context, our brains are already programmed to 'automatically' shift our view if we want to see something off-screen. I game on three monitors, and while I'm sure there are often things I want to look at hidden in the bezel, I can't remember ever noticing. I just automatically shift my view. I think it's interesting that in 1st or 3rd person view, I rarely actually physically turn my head while gaming, I mostly adjust my view in game. I don't think I'm alone in that regard. What i like about eyefinity is that it fills my peripheral vision. I don't actually turn my head to see what's on a side screen (I move the mouse instead), but I find having the peripheral vision filled is much more immersive.
In my opinion, it does look odd however if a helicopter flies past and appears to magically becoming longer when it passes through a bezel - which is what would happen if you didn't run adjust for bezel compensation. For me, that takes me out of the illusion of the game.
At windows desktop, I agree it's annoying when things pass behind the bezel. I've taken to just disabling eyefinity when I'm not gaming. It's a bit of a pain, but a much better experience. When I full screen something, 99% of the time I want it full screen on just one monitor. Apparently Hydravision can give you this functionality while leaving eyefinity on, but I could never get it to work the way I wanted (I gave up pretty quickly mind you).