You could always beef them up, square them off and put open shelving in between the two center ones. You would get shelving storage and make them useful. Maybe Glass shelves to use them as a display area.

or make a bookcase out of them.

I assume that they are structural. You could get rid of them entirely by putting in steel beams. A friend of mine did that - it is a very big, very expensive job, but it is an option. I like the shelving idea; you could also put in a half wall if you want to separate the space. Certainly square them off - it will update the look.

I am thinking making them square and adding a horizontal bookcase could be an easy and not too expensive option, right?

Keep the suggestions coming :)

if you run a steel beam you could eliminate some of them to open the space further. Otherwise I'd recommend curved archways as a way to divide the space but create some architectural interest.

I think I would just square them up (like in the crisp architects photo above) to bring them up to date. They don't really seem to be in the way -- whoever laid this room out has almost used them to divide up the space. As you can see in the photos above, posts and low ductwork are just things people expect to see in these basement rec-room spaces. I would just make the post "current" and not put any more money into it then that.

Book shelves on the side opposite the kitchenette and a bench on the kitchenette side with a dining table.