Certainly nothing wrong with using regular luggage instead of "dive" brands. Whatever fits your stuff, meets size/weight restrictions, and is easy to haul around. Though I've found that hard suitcases don't work out as well as wheeled duffles for dive travel. Partly it's the weight issue, partly soft bags are easier to stash on a liveaboard, and partly something with some give actually seems to hold up better. When we stuffed the hard suitcases we used to have (not even cheap ones) with heavy and sometimes still damp gear, they got yucky and beat (broken wheels, cracked corners.) That was when you could do 70# which didn't help, of course.
We have these and love them -
http://www.eaglecreek.com/bags_lugga...V-Trunk-20127/). Before that we had some fairly inexpensive but decent wheeled duffles that worked ok. They had a hard bottom but only a soft handle rather than a pull out rigid handle, and that was a pain.
Don't feel you have to pack all your dive gear in one bag and your clothes in another. We distribute things where they make sense, using clothing for padding. Also, some people will try to get one bag to fit 2 sets of gear for travel, which I don't think is the way to go.
Mesh bags are for local use or the boat - not to check on a plane. If you travel it's nice to have one you can fold up and pack along with everything else. You can get a pretty durable mesh bag with backpack straps that packs small enough and is very useful in most warm-water places.