Get the Nikon 50mm f/1.8. You can shoot indoors/in low light without a flash. If you want to do portrait-type shots, you might want something around 100-135mm. However, a fixed-focal in that range isn't cheap. If you are happy with the quality of the 28-80, I'd say just replace it with a 28-105mm f/3.5-4.5, or maybe a 24-120. Either will give you a broader range, including prime portrait territory, more speed, and probably better quality.
If your primary interest is photographing your children's portraits and activities you should consider one of the newer 28-200mm zooms. It will allow to to shoot outdoor activities without a lot of lens changing and the resulting chance of missed shots. The Tamron 28-200XR and the new Sigma 28-200 Compact are very sharp and crisp. They are light weight and not expensive. I just got the Sigma Compact for $189.95 from Focus Camera (call them, it is not yet on their website or in their ads). I have gotten many things from them without a problem. B&H has the Tamron XR for about $329 and the Sigma Compact for $249.
It's true that shorter range zooms are a little sharper, but if you are not making larger than 8X12 prints, I don't think you will mind the difference.
lense. I am now ready to "broaden my horizons" and would appreciate advise on the next lense I should purchase and where am i likely to find the best price? I primarily shoot my kid's portraits, activities and nautical/beach scenes.
Thanks.
I don’t like to give such kind of advices as everyone has particular needs I don’t know, but I would suggest considering the Nikkor 70-300/4-5.6D and maybe the Nikkor 28-200/3.5-5.6D.
My camera also came with the 28-80mm G lens. My next lens was a Tamron (572D) 70-300mm Zoom lens. I made the right choice for me, but that doesn't say that it will be the right choice for you. I guess you have to ask yourself, what do I want to do with my new lens, or what kind of shots am I missing most with my current equipment.
I will say that my next lens will be a Nikkor 50mm f/1.4 or f/1.8.
My suggestion is to first ask yourself if you are satisfied with the lens your currently own. If not then you may want to consider replacing it with something in the 28-105 or 28-200 range.
If you are happy with it then you must decide do you wide-angle or telephoto as your next lens. If it's wide-angle you might want to look at a prime lens like the 20 or 24. If it's telephoto, look at something like a 70-300 or 75-240 or 80-200.
If it was me and I was happy with the current lens, I'd go with the Nikkor 70-300 and then the 20. If budget was not a problem my first choice would be the Nikkor 80-200 f/2.8.