I'm currently reading 'Think before its too late' by Edward De Bono. Its not about software at all, its about creative thinking and breaking out of the patterns that we get stuck in. Exactly what you want when brainstorming about a new product or business.
Not too many software-specific books I can think of, but a couple you probably already know:
"Founders at Work" by Jessica Livingston - profiles a bunch of successful technology startup founders, mostly software.
"MicroISV - From Vision to Reality" and "The Web Startup Success Guide" by Bob Walsh - both software-specific books for startups - one more desktop product oriented, the other, obviously web-focused.
A while ago Steve Blank (customer development guru) recommended "Marketing High Technology" about the Intel marketing wars in the 80's... I'm still int he midst of it, but I think it's very good.
Built To Last
- by Jim Collins co authored with Jerry porras based on their research project at Stanford University.
Though, this book is not about software business, I truly feel this is a must read book for every business man.