They have it in Railcraft. They have it in Gregtech. They have it in Traincraft. They have it in Universal Electricity. They have it in Tinker's Construct.
That's right, Steel. One of the most (or maybe the most) manufactured materials in history.
It just makes sense. You can't have a mod with modern technology without steel! Steel creates millions of things, and hundreds of millions of tons of steel are made yearly. Steel is used in almost everything, computers, cars, everything.
Anyway, I firmly believe steel shouldn't be easy to get if it's IC2. Putting an iron ingot in a furnace is lame. IC2 deserves better. More then a multiblock furnace. It should have some risk to it, some art to it. It should be cool. IMO.
What would steel be used for in IC2? I don't know. Tools and Armor would be good. IC2 pipes? IC2 tanks? Super-cool boats? I know some people could think of better ideas then mine :p