The 50mm was the standard issue lens ('kit' lens) when all were film cameras. It grew back into fame with DX cameras, as it resulted in an equivalent 75mm lens. Being the D600 an FX body, I would go for something else, or get the f/1.4 for selective focus shots.
It's hard to give advice when we have no idea what you want to shoot.
50mm is a decent first lens, but a prime has limited application. As far as speed, I like 1.4 for selective focusing and low light applications. I have also found f1.8 or f2 lenses to be just fine (and sometimes sharper) and much less money.
For most people, a zoom is often a good first choice as the variation in focal length and field of view give more photographic options.
Despite historical precedent I'd suggest that as a first-first, I'd go with a zoom lens. while "what will you use it for" is a good question I'm also going to interpret the 'first-first' to mean it's likely your interests and needs may change as you go.
A 50mm prime is a great lens and I have one (I bought the F1.8 because I will use it for sports and it focus faster), but I'd suggest you look at alternatives that go both wider and longer (24-120 for example).
If your first lens means more will soon follow that's different, but if you expect this to be the only lens for a while I think you'll find that really nice camera a bit limited by a fixed focal length lens, even a very useful/good one.
Many people refer to 50mm 1.4 as low light lens but I have not had any acceptable IQ results from this lens when I use it wide open (f 1.4). First of all, focus is challenging as very selective range. Plus, if I compare the results with 24-70mm with f 2.8 with higher ISO to match 50mm with f1.4 in a give ISO range, I have better results from 24-70 2.8 (with higher ISO) than ones from 50mm 1.4. Maybe this is just me ???? But I am not quite satisfied with it. This is the lens that I carry often but use very seldom.
A vote for the 50 f1.8, I've had a 50 f1.4 AFD and it was just a bit soft wide open, better at f2 and on. So why pay the extra money for the faster f1.4 lens. The 50 f1.8 is a great value for a 'normal' FX prime lens in my opinion.
For a first lens though, a zoom may be more versatile and fun to use as others have mentioned.
This past basketball season I purchased a 50 f1.8G lens to go with my 50 f1.4G. After trying both lenses, the keeper, the one that consistantly took great pictures was the f1.4G. I used it on a D700 and loved the results. Some say the f1.4 is slow to focus. It's not! The f1.4G is just as fast as the f1.8G lens when focusing on player running and shooting on the court. The bokeh from the 50 f1.4G is also much better. Because I've proven to myself that the better lens was the faster 50 I gave my son the slower lens to use with his D300s. Next season I'm hoping to compare a Sigma 50 f1.4 against the Nikkor 50G lenses.