Right now I only collect 1:6, but I do have 8 SW PFs.
Moving into a new house has made me change my collecting habits. I realized in my old home that my collection was looking way too cluttered. Since I don't want that in the new place, I'll be moving away from the PFs (it's been a long time since I bought a new one anyway) and being much more selective when it comes to 1:6.
i think it depends on how well each one is done. for instance, hot toys 1/6 > sideshow, but sideshow PF & 1:1 > hot toys 1/4. my new order of preferences:
1:1 , 1/6 , PF
Premium Formats are the best collectibles I ever seen. I'm also start to collect Hot Toys 1/6 scale figures like Dallas and Kane and Iron Man. Try to limit what I get. However, Maquettes are also on my priority list like Jaws, Species and Juggernaut.
A little bit of everything - anything that fits my Star Wars OT Imperials focus or other movie lines that I like. Statues, PFs, dioramas, replicas & props, 1/6, even a few smaller action figures.