It is better to work with RGB or CMYK ?

[Thelonious]

Depends on how you are going to use the final product.

If you want to show it through email or if you want to print it on a home inkjet printer then save in RGB.

If you want to print out as a commercial size inkjet or a commercial laser printer, then use CMYK.

[handrawn]

There appears to be a thread duplication here? see this link:
http://www.talkgraphics.com/showthread.php?t=26586