Most of my programming has come from Crossfit.com, Crossfit Golden and Vintage Crossfit (Comptrain). Last summer I mixed in long runs, tempo runs and speed work. Over the winter, my running has been strictly weather dependent. I often rode my bike on the weekends. This winter, I have set up a trainer and have been following TrainerRoad.
For variety, I took a stab at kickboxing style workouts and gave Convict Conditioning a try in order to change things up and keep my workouts fresh.
I rarely come across a workout that I do not have the equipment for. Crossfit.com occasionally requires a GHD and Comptrain often calls for a bike erg. It is very easy to include an alternative movement.
I have added several luxury items to my gym including more weight, rower, wall art and change plates.
Unfortunately, I have also added a lot of nonsense that I do not use often enough to justify. These include dumbbells, steel mace, curl barbell, additional bands, silencer pads, weighted vest, squat box, and medicine balls. I have also somehow amassed a quarter ton of plates at an average of $2 per pound.
I still recommend everybody start a gym with flooring, barbell, plates, rack, and bench. Roughly in that order. This can set you back $2K pretty easily.
Then you need to assess your goals and training methodology.
Cardio equipment could be a rower ($1K), bike erg ($1K), ski erg ($1K) or treadmill ($2K-$3K). Pick 2 and it will set you back $2K-$3K.
Crossfit workouts can be modified ad infinitum and there is an equipment free stimulus for all movements. However, to be fully outfitted, you are looking at another $1K.
Strongman should be the cheapest unless you get specialized equipment for competition. If you go full on with yoke, strongman log, circus dumbbells, farmer's walk handles, you could be looking at $2K+.
Bodybuilding requires the most equipment and training for aesthetics often requires machines for safety and efficiency. This requires a tremendous floor space and $10K+. One may argue that a functional cable machine could replicate a lot of movements, but I disagree.
Powerlifting and Olympic Weightlifting requires the least amount of equipment, but it is still important to do accessory work.
For my personal needs today, my minimum gym configuration is flooring, gym timer, barbell, plates, rack with pull-up bar, abmat, jump rope, and kettlebell.