This is an excellent question. I pack differently for work travel than vacation travel. I'll answer this for vacation travel, which is usually of longer duration than a business trip. Even if I'm gone two or three weeks I will only bring a carry-on and a personal item. I never check luggage.
I think my biggest/bulkiest luxury item is my Bose headphones. I only use them on the plane on the way there and back, and then have to tote them all around in between on trains and everything else, and usually in business class they give you nice headphones anyway, so it does seem silly. The amount of space these take up for how long I actually use them is probably a waste. I just like them so much, though.
Other than that, I've really got my stuff pared down to essentials.