I don't ever see this discussed here. The level and focus of discourse here should make for great recommendations.
<edit> Should this be restricted to "on topic" material? </edit>
Me, recently and currently:
http://www.amazon.com/About-Face-2-0-Essentials-Interaction/dp/0764526413/ref=sr_1_12?ie=UTF8&s=books&qid=1251767831&sr=8-12
http://www.amazon.com/Matter-Great-Design-People-Company/dp/0137142447/ref=sr_1_1?ie=UTF8&s=books&qid=1251767882&sr=8-1
http://www.amazon.com/Positioning-Battle-Your-Mind-Anniversary/dp/0071359168/ref=sr_1_1?ie=UTF8&s=books&qid=1251767926&sr=1-1