As Viera4 says, if you've got light control, a grey screen isn't necessary. A lot of the darker screens have high gain and this comes with issues such as directivity (if you're on an angle the picture is hard to view, like early LCD screens) and hotspotting (where the center of the screen is brighter). Plus high gain usually = high price.
Having light coloured walls is not ideal, but doesn't mean a grey screen is needed. Stopping light leakage around the edge of blinds is much more important.
Whereabouts are you? Sounds like it might help if you and the wife could see a proper set-up.