have you tried removing all styles from the layout object? It sounds like some wierd backend display mojo is cutting your words off. Also try readding the field with the radio button field tool so it forces the default theme settings.
And just to piggyback on what Mike suggested - I suspect this is probably caused by having too much padding in the field that value list is attached to. You can control the padding in a field from the Appearance tab of the Inspector.
Yep. That was it. Padding. New feature, eh? Thanks for the tip!