I have 3 bags at this point. One nice leather over the shoulder bag. Something like this, except it's a top loader:
In that goes the laptop, charger, notepaper, small screw driver, external drive (HDD and DVD), roll of velro, and a couple of patch cables. It's the stuff I used on almost every job.
Then I have a little craftsman softbag like this:
It's my "troubleshooting bag." I have a toner, crimpers, side cutters, punch down tool, box cutter, and larger screwdriver. That's the one I grab when something on the network isn't working.
The third one is my installer bag. It's something like this:
It has my butt set, two more toners, a cable testor, more hand tools, fish tape, misc screws for racks, etc All the stuff I usually need on an install or big cabling job.