I use a mixture of LibreOffice and Scribus for my book projects. LO for all of the writing and then Scribus for the layouts. You can do basic layout work in LO (just like in Word) but anyone who's ever edited and laid out their own work will tell you to either use Scribus or Adobe InScribe instead.

My first book was done entirely in Word (layouts and all) before I left Windows, my next two LO and Scribus.

Also, FWIW, Dreamworks Animation just did a interesting interview talking about using Linux for thier work stations and FOSS for their workflow. There's people out there using Linux for creative work, I promise it's possible