I'm on a 3 night trip right now and the following is what I do.

First, I have a packing list spreadsheet built with formulas. I just punch in the number of nights and it'll give me a general idea on what to pack (or what not to forget to pack).

I pack very little toiletry. I once cut my regular toothbrush short to fit into a ziplock. I now use a travel toothbrush.

I always roll my suit. I also pack the bare minimum and avoid things like a 2nd pair of shoes if I can.

I have 2 one bag options. For 1-3 nights, I've started using a ThinkTank Streetwalker HardDrive. It's a professional camera bag and it has padding on the side and flexible configuration inside. This helps greatly when I don't have a lot of clothes and still want to compartmentalize an area for my suit.

For 3-5 nights trip, I use a Timbuk2 Wingman. It can hold A LOT of stuff. I also use packing cubes in this case.

Accessories:

If I fly, I would bring a travel extension cord.

I use Grid-It as well.

I have a pair of travel slippers that one of my relatives got from a business class international flight. It's good as it's soft and foldable.

I just got these shoes, and so far so good. It's very light and versatile. It's much cheaper to get them from other online retailers.

I have a Timbuk2 Quickie for my laptop and iPad. I slip that into the laptop compartment of my bag and then pull it out when I go to a meeting.