Now THIS is a book I'm gonna get in time for the holiday season! Concentrating wholly on intermediate-to-advanced interface design,
Designing Interfaces is an O'Rielly book with a difference! It privides rather specialist advice on designing interfaces for Web, CD, application or "smart" device delivery, and features more than its fair share of design theory and practical examples. Very useful stuff really! It can be purchased for $49.95 USD on the O'Reilly site.