Originally posted by iL Medico Unless your house is extremely well lit compared to mine or most I've been in, you will struggle to get anything above 1/50 at ISO 1600 at 1.8-2.8.
What may look bright to the eye is really pretty dark to the camera.
I can turn on all the lights in my living room/kitchen/dining area, plus the big screen TV and at F2 ISO 1600 I'm looking at 1/20 t0 1/60 or so depending on where in the room I am.
I would get the flash unless you have a LOT of light or no one actually moves
Yeah but you can also hit the little button to pop-up the onboard flash and get a person or two in the average living room/kitchen/dining area.
If you are just trying to catch one or two faces in an average room the pop-up flash will likely have enough power to make it across the 'average' house's room. If it is supposed to be a group across a larger room or a portrait or some serious work you may find that the pop-up is too limiting. If it is an average indoor lighting of the average elementary school gym or high school gym you should be able to get the shutter times above at 5.6 and maybe if you are lucky at 800 ISO, but still too slow for basketball. Now if it was an average college or better gym you will likely find even better lighting but still minimal for a camera especially for action and too much distance to cover with the pop-up.
What good is a body, a grip, a flash but no glass? If it were in my gear bag I'd say it was a back-up but if you don't have a primary pakage complete with glass...
But I think if you think of what type of pictures you want to be capturing you will be the best person to decide the order of aquisition.
My first Pentax system, a Super Program, in order, over about a week was the body, 50, 28, AF200T (or some such small Pentax flash), and 70-210. The system continued to grow at a slower rate but included a much better flash down the road. That first flash was the closest thing to a pop-up back then and it worked well in average indoor lite rooms, until my needs required something better.