I think it depends on what is your definition of complete. Hahaa. If ure looking to keep fit I feel that running is the best way to do so. I would say investing in a proper running shoe would be a pretty important "equipment" to have.
That is definitely straight up gangsta when you're using a bus stop as your workout equipment damn! Some of these dudes look a lot better than the gym rats trying to bench. Stuff like this makes me think the concept of a gym is BS sometimes.
Just like what Luxy mentioned above, it depends on what you meant by complete workout? I don't have any special equipment when doing some of my daily exercise routine (which I may add I sometimes miss). When I miss my daily work out at home, I do little bit of workout at the office. I use whatever is available to help me perform my exercise even with limited space. You can use whatever is available around you, like chairs or pen.
I believe it is possible to do a complete workout without equipment. That is, if you consider a complete workout to mean you would perform a variety of muscle-toning push-ups and crunches as well as buttocks and thighs movements, it would be complete. Another word for it would be "comprehensive," because it includes both aerobic and anaerobic routines.
I agree that it could defends on what you would like to achieve. And also there could be "improvised" equipments that can be use around such as on the video above.
I had seen a workout video before that does not include any equipment. It was combination of squats, high jog on place, push ups and jumping jacks. And it seems "complete" since it involves the whole body and looks intense cause you will really sweat a lot doing those exercises.
If you just want to stay fit and healthy with a light workout, I think a run and then some core exercises would be fine. However for me I would need machines to motivate me when wanting to pack muscle. I just love lifting weights and using treadmills.
Most neighborhood parks have fitness corner. You can find chin up bar, dips station, monkey bar there. Be creative when using these stations. Bodyweight exercises done on these stations can be a great workout too.