Samsung EX 20mm F2.8
20mm f2.8 is my favorite lens, it's on my NX10 90% of the time. The other 10% being 30mm f2.0. I am not a fan of the kit zoom.
20mm is not as sharp as the 30mm, and the bokeh is not as "pleasant" (this is very subjective) as the 30mm, but choose the focal length based on the type of photography you shoot. You might think it's only 10mm difference (between the 30 and 20), but it's a big difference between "normal" and "wide". Don't buy the 20mm as a substitute for 30mm because it's on sale.