I’ve had several crashes of galeon and firefox recently. Removing the damned non-free flash plugin helped. This might be related to xorg - I know at least one other program - qiv - which does not work with xorg (maybe recompiling works, I havn’t tried).

Update: Robert McQueen said that qiv runs fine on his sid + xorg/hoary system - pretty much the same software setup I have here. OTOH, someone else filed a bug against qiv with the same error message, and he is also running xorg.