Depending where you live and if your dirt is caked on dirt or just loose dust a pressure washer and foam cannon alone may work for you. In my climate it's not really viable, there is a layer of dirt underneath that needs something more to be removed. It rains almost 200 days out of the year here so I also want a product that helps beading to keep my car clean for at least a few days, maybe even a week if I'm lucky. Today I just washed it today with the following process after about 2 months of winter storms and being too lazy to clean my car.
1: Touchless powerwash with foam cannon for about 5 minutes, then about 5 minutes with a clean rinse. This is just really quick to get the worst of the dirt off, leave debris, etc. Also I was sure to spray the undercarriage as much to get rid of any salt residue kicked up.
2: Went for a spirited drive for 15-20 minute to get the worst of the water off. I'm too lazy to do it by hand or with an air blower and this is way more fun!
3: I then use sanzo waterless car wash spray on the whole car, one panel at a time. First you wipe off the dirt with a "wet" microfiber, then follow up a buff with a clean "dry" rag. The finish it leaves is amazing, almost wax like, although it only lasts about a week.
4: Tire shine, interior detail, vacuum, wipe down surfaces, and glass. This is the easy part, except glass, I hate doing glass.
Final results from today (about 1.5 hours work)