We had carpet in our basement. Then we had the Great Flood of Walt Disney World 2003.

In the wee hours before we were due to fly to WDW for our Kellogg's Sweepstakes Family Vacation, our water heater ruptured and flooded our basement. We did our best to drain it before we left and FIL took over so we could go ahead. When we got home, the mess was unbelievable.
We swore we'd never carpet down there again, BUT we have 2 bedrooms and a playroom, so decided to do it anyway (after putting in a tankless water heater

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We used Legato carpet tiles from Home Depot and I LOVE them. (
www.legatocarpet.com) They fit together seamlessly, clean beautifully, and if the kids happen to grind red modeling clay into one of them, it's easy to lift it up and replace with a new one. We used a runner down the stairs, then the Legato in the hall, bedrooms, and playroom. It has the pad and a moisture barrier built in, too, so that's nice. It was a weekend DIY project. The nice thing, too, is that DDs want to change their room decor a bit, so we only have to pull out what's in their rooms, not the whole basement. Actually 8yo wants 11yo's carpet, so with a little tweaking and a few extra pieces, we'll be saving some on the remodels. We've used carpet "squares" before with not-so-great results, but I can highly recommend Legato.