IE is always positive.
First electron affinities are generally positive (EA is defined as the energy released on accepting an electron, so negative ΔH equals positive EA). A few elements, particularly the noble gases, have negative EA, i.e. the negative ion is unstable.
Second and higher electron affinities tend to be negative, because you are adding an electron to a negative species. Thus O2-(g) is unstable relative to O- + e, but O2- is stabilised by the formation of solid oxide lattices.