Green Ronin updates their two books covering Demons and Devils to 3.5. This book also includes the Yugoloths/Daemons/Neutral Evil fiends.

Lots of really original fiends that can be used with any 3.5 compatible products. Writen by Green Ronin guru Chris Paramas and d20 expert Erik Mona. Over 130 new fiends and details on their lands.

The only downside is the fiends are not shown in color, which would be great.