Every one's use case is different, for me I need to cover long exposures with telephoto lenses for my landscape work and to stabilise a large heavy wild life lens in high winds and difficult terrain.
My Main tripod legs is a Sachtler Flowtech 75. It is by far the most stable and versatile tripod I've ever used. It's so fast to set up and use. However, it's quite big and comparatively heavy. It is the last word in stable photographic tripods. I bought it initially becuase my previous main tripod (Gitzo Systematic GT3541LS) wasn't sturdy enough for my old EF 400mm f2.8 LIS (which is a heavy beast of a lens). As my Gitzo was getting old and worn, the twist locking components on the legs were sometimes not locking and would slowly creep under the weight of the camera & lens. My current EF 400mm f2.8 LIS mkII is a LOT lighter and I'm finding that it taxes the tripod a lot less!
I use only one head, a Flexshooter Pro, which is a hybrid ball head. It's nearly a great large ball head which is perfect for general and landscape photography, but it's also nearly as good as a gimble head or Fluide head...so it serves as me as my wild life / birding head of choice in additon to my landscape needs. For me...it's "One head to rule them all!" This replaced my long term Markins M-20 and Gitzo G1380 Fluide head.
I've just bought a mini travel tripod, a SmallRig AP-10. My Flexshoot pro fits this ok, although it's a little top heavy. I might invest in the Flexshooter Mini just for this tripod and for travelling lighter. The ratio of size, lightness, portability and stability are in a class of their own. Is it as stable as my Sachtler? No, not eve close. Is it good enough for 95% of my needs...yes it is and it can handle my big lens too. The tripod is only 52" high and the top plate is only 60mm in diameter. But fully extended, the legs do not bend or flex with my heavy load. The weakest part of this tripod is the supplied ball head. It's beautifully light but too small for serious work. The ball is only 28mm and is easily overwhelmed by heady loads. The top clamp plate is too narrow to faithfully secure any large L plates or Lens plates with confidence. These legs are a replacement for my long term travel tripod (Gitzo GT1541T) and Markins Q3 head. The Gitzo is slightly more compact, but a little heavier. Without the central column it's a lot shorter than the SmalRig and it's no where near as stable. The legs are just too thin and bendy to stabilise my large 400mm lens. At max extension it's just too short and it's really fiddly to unpack, extend and put away. It's also got Gitzo twist locks that gradually fail over time and with exposure to salt water.
I have a old non-carbon fibre Manfrotto monopod that I hardly ever use unless I'm shooting an event where I'm chair bound. I've often thought about repalcing this with a light weight option. However, I just don't use it enough to warrant a further investment.