I take my shoes off (and generally ask if people mind me doing this within 5 minutes at complete strangers' houses). If i'm wearing socks or tights i walk round in them, if i'm not (mostly in summer) i walk round in bare feet.
I would want to keep my shoes on if there was a noticeable cat or dog presence in the house though. Although, if there was a dog i'd want to stay outside the house altogether, so...
I've nothing against slippers - i have a couple of lovely pairs - but i never get into the habit of putting them on. And they do tend to stop your toes wiggling somewhat. which is a bit stressful.