I've got a "human" 10 year old indoor male cat that is entirely incredible.
I've never had a spraying, clawing, escaping or discipline problem with
him.  However, last week, while suffering from a severe cold I made a first-
time mistake of placing his catbox in it's normal place (a carpeted closet)
in an abnormal position (with the entrance to the catbox facing the wall)!
Due to my cold and bedridden mode, my keen sense of smell didn't pick up
that he couldn't get inside the catbox and was defecating and urinating on
the mat and closet carpet directly outside of his box ... until almost a
week later.  

So my questions to the group are two-fold:

(1)  I've removed the carpeting and padding from inside the closet and want
to find a way to ENTIRELY remove the remaining urine odor.  There's Urine-
off, products from Planet Urine, and many others, but I just don't know
which one would really do the job.  Anybody have feedback as to which
product REALLY works to remove urine odor from carpet and/or hardwood floor?

(2)  The reason I ask about carpet, is because I'm thinking of placing some
loose carpeting in the closet for his comfort, it's easier to clean and
looks better.  Does anybody have advice on the best flooring to have and
preserve in a non-odorous manner if there's ever a cat mishap?  I'm
debating whether to go back to loose carpeting and remove the carpet itself
should there ever be an accident.  Or should I keep the hardwood floor with
a cat mat outside the box and attempt to preserve the floor itself.  

I'd love to hear your feedback and advice for urine-odor removal products
and the best way to maintain a litter-box closet that is clean and odor
free ... allowing for an occasional accident.