By LBV, I'm assuming you mean something more than just a safari/photo vest.

I like one that is as open as possible- what isn't pouches doesn't need to have material under it. But it also shouldn't LOOK tactical. Avoid anything that looks like it was worn on Stargate- unless it is halloween. Avoid black, avoid camo- OD, tan, coyote, foliage are the best bet. The fewer pockets, the better- a bunch of small pockets looks more "interesting" and one or two large ones on each side. Try to keep it as much as possible the same color, at least your pockets, with the straps a contrasting but close color if they they can't match, so they look like "trim".

My personal pick is the Tactical Tailor MAV. It can be swung around and worn as a lumbar pack- it becomes invisible at that point. And with a large pocket on each side, and a pair of small ones for pint water bottles, it looks almost like a fishing vest. Add fleece patches to the front of the large pockets, I doubt anyone who isn't a hard core gear junky would see it for what it is.