Since I travel a lot of business and do plenty of conference calls, I gotta say my Panerai PAM156 GMT watch and Rolex GMT II Ceramic on a bond NATO strap.
Rolex. I was a fan of theirs for many years, but couldn't bring myself to spend that kind of money on a watch - until I met a man that was wearing a 1985 that his wife got him for there anniversary or wedding... i don't remember. I do remember that he told me the only times he had taken it off were when his job required it (mechanic) and it had never needed serviced. That sold me. *I had to ammend this post; Victorinox / Swiss Army is my favorite brand, with Rolex as a close second. I've always liked Victorinox watches, except for a few features that I didn't think they made. I just found a Victorinox watch that might as well be a Rolex Day-Date, but it's steel instead of platinum, and one tenth the price.
Maybe I'm a bit of a simpleton but I still fancy the Casio outdoor/ divewatch I bought about 18 yrs. ago.
I've always liked Seiko & Citizen, not knowing better, but in the past year or so, I've become a big fan of Breitling and IWC. Rolex is up there too. I find myself reading about Rolexes and seeing the evolution of some of their watches with a lot of interest. All three are very good watches, but I won't be able to afford one for a very long time. G-Shocks are also great. I've owned two so far. Suuntos look very intriguing too, but I haven't gotten the chance to own one yet. Hopefully soon...
I've had the same Seiko Dive watch since I graduated boot camp in 1975. It still runs better than I do. Just bought a Bertucci A2T all titanium, so far so good.
Luxury: Rolex Victorinox/Swiss Army Omega Breitling Everyday: Casio G-Shock Casio Pathfinder Swiss Army/Wegner Seiko Timex Ironman