Since I'm an artist myself the first thing that comes to mind when I think of decorating is what to hang on the walls. It's customary to fill the largest wall with an over-sized oil painting and for that I recommend something tasteful, something like this one (above) by Cliff Sterrett. It's restful in it's way but it's also stimulating and manly.
It's also customary to have a small accent painting nearby. How about something something quiet and understated like this (above)?
Males like to have a picture of an undraped woman on the wall (above) and male cartoonists are no exception. It adds a touch of class to a room, reminding us of the great pictures of the old masters.
A sculpture or two wouldn't be out of place. This one (above) is by Brancusi.
Whatever you do, never buy Laura Ashley-type furniture. It's fine for non-cartoonists but it's lethal for people of our breed.
This (above) is more like it. A cartoonist can't think without a certain amount of leather and wood around. And don't forget the stuffed animal heads. I'm an animal lover so I'd substitute fake heads. They get more realistic every year.
Of course cartoonists naturally want a little color and design in their lives. For those who prefer soft, mushy furniture why not use colorful coverings like the kind in Cliff Sterrett comics (above)?
For additional spot paintings I recommend the kind you see on the walls in the backgrounds of Smokey Stover panels (above). Be sure the hanging wire and nail are visible.
Last but not least, I think a framed portrait of some inspirational hero is in order. Something that'll get your juices going when you pass it in the hallway. For me that would be Bob Clampett or Percy Dovetonsils. Ah, giants walked the Earth in those days!