Even though you're pretty committed to the carpet tiles, I'll put in a vote for the vinyl plank flooring. We've done that in both our DR and LR. Both purchased from Home Depot and DH did the installs. The biggest downside for me is that the floor is cold but that's probably more a product of having our front and back doors almost aligned and having air gaps in the back storm door.
The first one we purchased the brand was 'Allure'. I like it better than the brand they are now selling and we have in our LR. But it's still a better clean up than carpet, especially with the furboy. I don't have to worry about spills and such.
Don't know the cost comparison between it and the carpet tiles.