Do you come back from 3 day vacation with over 500 pics?
Well, I come back with way less shots and more keepers. How? I got my DSLR back in 2006 and it came with a 1 GB CF card. It gives me around 120 shots at 8 megapixel in RAW format. 120 shots seemed too less when I started off and I thought of upgrading to 4 or 8 GB card but, not sure why, I never added memory capacity. I still shoot with that same 1 GB card even today.
Now, in hindsight, after shooting for close to 7 years with that 1 GB card, I think it has actually worked well for me. Remember the days of good old film cameras with each film roll of 35 exposure (and if you fill the roll creatively then you could milk 3-5 exposures more)? Most of my outings back then were covered in 2 such rolls and that's around 60-70 images. Back then we were not this click happy and shot everything that came our way. Limited fire power kept our life simpler and vacations more personal. This is where my 1 GB card forced me to look more and shoot less as I knew that I had only limited shots I can make before I will have to flush the card.
In this age of virtually unlimited number of shots you can make on a single card, try to restrict yourself before clicking that shutter so that you spend more time studying your surrounding, talking to people around you and shooting through your eyes and then pressing the shutter only when you are convinced that you are making a good shot. Obviously, this won't work for action shots and other super fast activities you shoot but give this a try for your next vacation and you may just end up with less but more thought out pictures.