What Camera Should I Buy???

Okay here is my situation. I currently use a Canon 20D and I absolutely love it. I still have a Canon 1N film camera that had been collecting dust. I started carrying it with me in my car just incase there is ever "that time that I need a camera." The problem with it is that I have become spoiled by the availability of digital images. If I take a photo with my 1N while I am out and about I either have to wait and finish the roll or waste film and rewind before the roll is complete. Plus the cost of film and developing.
Here is where I need suggestions. I would like to buy a nice 5 MP camera that I can carry with me at all times. So I need it to be rugged and reliable. I have used a Canon G5 in the past and liked everything about that camera except the shutter lag...maybe it was just me but I seemed to miss some shots do to the lag after you hit the shutter button.

This is what I would like:
A rugged build.
Low noise at ISO levels
Max. Features
Very min. shutter lag (this is most important)
5 MP
Uses Compact Flash (Although I could live with another format / just convienent since I have the 20D)
And I would like to stay around the $300-$500 range.

Any suggestions would be great!!!

Thank you