Shabby little response there, MtK. Wot Gertrude can't say anything because she disagrees with you? Especially since you admit you can't do without Windows for "complicated graphics".
meagre experience,
If all your spreadsheets have 3 tabs called "Sheet 1", "Sheet 2" and "Sheet 3", of which only Sheet 1 is used, then yes I guess Linux and OpenOffice will work for you.
One benefit of being a Linux user is that after you run out of fun bashing Windows, you can always start knocking others' choice of Linux distribution.
Meanwhile, the Gertrudes of this world are using whatever tool gets the job done.