My SO and I tend to go the route of having the toughest, inconspicuous luggage we can find.

His favorite is an Andiamo garment bag. He has racked up 2 million miles (not sure how many of those have been BIS, but it's been a lot of traveling regardless -- mostly domestic), at the airport twice a week nearly every week for about 8 years. While it was a bit of an investment at the time, it has held up amazingly well -- and he has been able to send it in to them for refurbishment at very reasonable rates (something like $50 to have all hardware replaced).

What he really likes is that there's nothing on the bag identifying it as Andiamo. The one label on it is blank. Just a patch of leather, almost making it look like some sort of knockoff. This is a big plus. There are times when he has had to pack equipment of one sort or another in it, and he feels better checking it knowing the bag doesn't look expensive.

That's one of my beefs about Tumi: The logo and label are so prominent.

My main case is a Briggs and Rilley 22" wheelie. Its logos (one on the case and one on the tag, which I'll probably remove) are pretty muted, and B&R as a brand is less known than some of the others.

Anyway, I wouldn't go with ZH for the same reason as Tumi. People are aware that the bag/case itself is worth something, and it can be assumed that there's something valuable inside of it, too.

For laptop bags, Bagreview.com is an excellent resource. I also like to read the reviews on ebags.

I don't worry about overheads. I always put my laptop bag (a Timbuk2 custom commute messenger bag, back when they did custom laptop bags) under the seat.