For me, it's using both, but in combination with my own material.
Creating house rules for 3.5 is one thing, but when a team of professionals revamp the entire system while keeping it familiar and compatible, I can't turn that down. I'll still be adding house rules, but it's great that so many I had before are now core rules.
As for setting, Pathfinder has reinvigorated so much of what I love about fantasy roleplaying, and it just happens to coincide with my most ambitious world-building phase to date. I've always used homebrew worlds, but in building them I also draw inspiration from published products or even borrow whole elements and just tweak them a bit and maybe change some names. Having quality published material like Paizo's makes fleshing out homebrew worlds a whole lot easier.