Originally posted by maltfalc both. autofocus zooms for situations with quickly changing/moving subjects and locations with fog, snow, dust, sea spray, etc.. fast primes for situations where you can take your time and want the best image quality you can get.
Exactly what I was gonna say.
It'll depend on your shooting style. When I'm on the road and I can't really stop every two minutes and take my time to find just the right spot, I have a super zoom on the camera (18-200). If I come up to a place where I feel I should take my time, I'll set up and either use a good quality shorter zoom or a prime. If I am doing portraits, I'll have a prime on the camera. I tried my 50-135 for portrait but I still prefer primes for this. If I'm going for a walk in the bush with the dog, I'll use a 17-70 I'm not into birding so I don't need the reach. A 50 would work good too but the zoom does give a bit of flexibility.
My goal was to cover most range with good quality zooms. I currently have 17-70 and 50-135 with a 10-20 expected Tuesday and a 120-400 next month. I shoot everything and anything. This kit covers it all. But it's big and bulky. And even with the DA*, IQ is not equal to primes.
After a while I have identified focal lengths I use more often and bought primes where I felt they were required. At the moment, 35, 50 and 135. I will later get a 15ish and either a 70, 77 or 85. At that point, zooms will become less useful.
Both your zoom kit and your limited kit will render great IQ. You won't go wrong either way. (I would add a longer prime like a DA*200 or 300 if I were you). It will depend on the level of quality that you are after. Even the DA 18-270 can take amazing photos, one lens and you're done... if you can live with it's limitations.
One thing I noticed over the years is that most "prime kind" of people will usually stick with primes and rarely get a zoom. Where the "zoom kind" of people will get some fixed focal length lenses at one point.