KLIPPBOK by IKEA: Going beyond simply being an IKEA catalog, this app lets you take items that IKEA sells and create your own collages or swatch books from them. It's helpful to use this app to compare several offerings from IKEA in the same category. iPad. IKEA Catalogue: iPad & Android
Design Within Reach: It's the biographies about the designers that take this app from just being a catalog full of beautiful modern design into something special. We love learning more about the history behind the pieces and think that DWR have done a swell job in how they have chosen to enter the app space. Our biggest complaint is that this app is not available on other platforms. iPad
ELLE DECOR Lookbook: A perfect app for browsing for inspiration. It's also fun to quiz other home design nerd friends on where they think the different decor items are from. iPad
Domino Best Rooms: We at Apartment Therapy loved Domino and so rejoice whenever we can have a little bit of Domino back in our lives even when it's only in the form of these small Special Edition highlights. Best Rooms is available on both Windows 8 and the iPad, Quick Fixes and Preview are iPad only. $6.99
We know that this list is by no means complete and would love to hear about what apps you use on your tablet to find just the right items for your home.
(Top Image: IKEA, all others as linked above)