Lumi, because starting interplanar war and executing millions of people for small lies is something that's both reasonable and non-evil. Good ol' wacky alignments.
Two outsider RHD aren't all that bad. The ability adjustments (+2 strength, +4 constitution, +4 wisdom, -2 charisma) aren't terrible either, though the implied caster focus doesn't go that well with the RHD. Free Improved Initiative is quite nice.
The special abilities are mostly immunities: Body of Light gives immunity to death effects, energy drain and negative energy effects, as well as being on the positive energy plane. Clear Vision protects the Lumi from light effects, being blinded, or being dazzled. Finally, Floating Head removes the bonus for flanking them in addition to preventing decapitation and strangulation.
Finally, the Lumi's SLAs are a mixed bag. Disrupt Undead at-will is mostly useless, Light at-will isn't great either, and 3/day Cure Light Wounds is hardly something to write home about (if nice to have), but 3/day Glitterdust is excellent.
Based on the good stats, varied immunities, and access one of the best level 2 spells, I think anything below +0 would be ludicrous, and the combination of various useful abilities is enough to push it to +1.