[Shadow]

Are ionization energy values always positive (that is, energy needs to be driven to the system)?
I think yes, but I need a confirmation.

Are affinity energies always negative?
I think not, but I need a confirmation.

[mjc123]

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 O^2-(g) is unstable relative to O^- + e, but O^2- is stabilised by the formation of solid oxide lattices.