I too have black rolling suitcases that look like 1000's of others.
I took reflective tape (that you can buy at auto stores) and made a distinctive marking around every handle on my suitcases. I used a couple of different colors, and the tape completely covers each handle.
Each suitcase marking is a little different (I bought expensive luggage, so I only bought one piece at a time over several years, and marked them as I bought them), but all the colors are about the same, and it's pretty obvious they all belong together.
One of these days, I'll get all of the bags out of the closet, and make all the markings identical.
I also put some of that tape so that it's visible on EVERY side of the bag - I put some above each of the rolling wheels, some across the front of the bag, the back, the bottom, and each side (if there's no handle on the side, otherwise, the handle is my marking). I frequently have to replace this tape (it does get pulled off or wears away after a while) but the tape on the handle I've never had to replace (after 8 years and multiple trips per year).
This REALLY makes things easier waiting at the luggage carosel, since you can see the bag when it first enters the carosel, and keep an eye on it until it gets to you. If someone else grabs it, you can easily tell they have YOUR bag, and not their own (I always wondered if that person across the row grabbed my bag and not their own until I marked mine). Presumably, the tape on the handles tells people that this is NOT their bag.
Some people run businesses out of their house so I didn't want them lamenating business cards that list their home address.
