Looking for a home design software  

The software won't design your space... Maybe start with pen and paper and then consult a professional.

Before getting on the 3D programs, start with the most basic first...an idea or a concept for your living room and kitchen.
Architects and interior designers (the good ones) are hired to do this not just to draw 3D shapes, that's a draftsman's job or outsourced to anyone with computer drafting skills.
Form making is not the same as design but a process tool. An idea or a concept can be realized without using a 3D/CAD software (based on my professional experience or look into Eero Saarinen's TWA now Jetblue terminal at JFK in NY).
I hope you are not one of those that thinks buying trophy furniture and objects for your home is design If it is, retailers like DWR and IKEA kitchens (and many others) have softwares available free of charge from their websites to help you furnish your home at your leisure.
Public libraries will also have drafting books with 3D softwares included for anyone to check out/borrow.

Wow.
Try http://www.sweethome3d.com .

Hi , thanks for your advices, This weekend we tried a 3D home design software by Home By Me : http://home.by.me/en//
It seems interresting

Another software you can use is Google SketchUp. I believe it is free.
http://www.sketchup.com
I worked as a concept designer and a set designer for animation and live action. I normally used Maya and Zbrush. BUT, for people without a background in 3D imaging, Google Sketchup is quite user friendly. And, I do, sometimes, used Google Sketchup to whip something fast.
Although I agree on the value of having a good designer to design your house. I say live and let live! It is your house and your money. You can do whatever you want with it. whether you choose to have your home designed by professional designer or not, the most important thing is you are happy living in it. I am a designer and I do interior design of my house on my own. But, i don't go around telling people that they have lousy sense of taste just because they don't use my service, or other designer, to do it. and the same goes whether or not they have better furnitures than mine.
Regardless, IKEA or DWR, it's your home and no one has the right to judge ;p