How can I keep my sharp edges with subsurf? Because I like that ‘lo-poly’ kind of look. But I also want something more realistic.
YOu can select the edges you want to be creased and use Shift-E to assign crease level, might work for what you want.
Shift-E is your best bet.
The other option would be to add extra parralel edges near your sharp edges. This gives your edges that little sheen effect. This however is a subD technique and not suited for lowpoly models because you would be increasing your polycount exponentially.
In addition, to keep these creased edges properly shaded (if you are using the Shade Smooth mode) add to their object the Edge Split modifier. Otherwise you will obtain a strange shadows along creased edges in the viewport and on the Cycles render.
Ah! I was having that very problem keeping those sharp edges properly shaded. I was about to ask a question about the subject, but stumbled upon your post. Thanks for the tip!