For our long trips, I actually bring 4 cameras, I know, I'm crazy.
1) Video Camera - This is not brought daily, for a 5 day trip, probably only twice.
2) Canon PowerShot SD750 - My super small camera, carried at all times, even at home since it fits in my purse.
3) Canon S3 - A bit larger, nice zoom, carried 1-2 times during the week.
4) Canon Digital Rebel - Super large, so only carried 1-2 times (I switch off between 3 and 4) with standard lens and 75-300mm lens.
1 and 4 are carried in camera bags. 2 and 3 go in a backpack.
I really stink at night shots, so I have never brought a tripod.