Yes, the Rokinon 12mm f2 is also great for astrophotography (probably THE best lens for this?) if you ever want to do it, great for landscapes, very wide angle shots of architecture (inside or out). It is manual focus, but not a big deal at that focal length. Small, light and cheap (I got it off eBay in very good used condition for £200, about $240).
As another poster said, if you're getting a 35mm prime, I'd consider the f2 - for the very fast focus, and although weather sealed can be over-rated, better to have it than not (both the latter will help if you're doing street photography, for example). Though I've heard the 35mm f1.4 has a very individual quality, so you won't regret getting that one either.
Having said all that, if you just used the 18-55mm f2.8-4 and nothing else for the next year, there's nothing stopping you taking a great set of photographs. It really is a fine lens.