Here are Non-BuildCraft Items that are needed to create or use BuildCraft items:

Cactus Green is needed to craft Pipe Waterproof.
Cobblestone is needed to craft Steam Engines, Cobblestone Pipes and Stone Gears.
Diamonds are needed to craft Diamond Pipes, Diamond Gears , Lasers, and Redstone Diamond Chipset.
Glass is needed to craft Pipes, Tanks, and engines of all kinds.
Gravel is needed to craft Structure Pipes
Gold Ingots are needed to craft Gold Pipes, Gold Gears, and Redstone Gold Chipsets.
Iron Ingots are needed to craft Iron Pipes, Iron Gears, Combustion Engines, and Redstone Iron Chipsets.
Obsidian is needed to craft Obsidian Pipes, Assembly Tables, and Lasers.
Pistons are needed to craft all BuildCraft Engines.
Redstone Dust is needed to craft Conductive Pipes, Chipsets, and many other items.
Redstone Torches are needed to craft Refineries.
Sticks are needed to craft Wood Gears.
Stone is needed to craft Stone Pipes.
Wooden Planks are needed to craft Redstone Engines and Wooden Pipes.
Dyes are needed to create pipe wires

Crafting Tables are needed to craft Automatic Crafting Tables.