I'm going to buy a Nikon D50 body, but which lens should I buy for all around use?
I'm planning on getting the 50mm f/1.8D. What do you think?
All round use is hard to answer. It depends very much on the person.
The 50mm f1.8 from Nikon is a very good lens optically, and for that low price it is almost mandatory. Nice as portrait lens, and when a low light lens is required.
But, with the 1.5x conversion factor of an APS-C sensor size DSLR, it is not a "standard lens" (50 x 1.5 = 75mm).
A better suited single focal point lens as standard lens is the 35mm f2 Nikkor.
More suited for alround use however are "standard" zoom lenses. The 18-55mm that is the standard kitlens from the D50 is actually your best choice if budget is limitted. Often underestimated, I actually put it above the 18-70 kitlens from the D70s, and definitely above the 18-135mm kitlens from the D80 that is a bit of a dog in my opinion (and not a very cute dog).
If you have more to spend, or need a more light sensitive (bigger max. aperture) standard zoom lens, the Sigma 18-50mm f2.8 macro or the Tamron 17-50 f2.8 (check if the Tamron focusses accurately on your camera) are attractive alternatives. So can be the Sigma 17-70 f2.8-4 macro.
It is up to you what you consider "all around use", for me all round use is 12mm up to 340mm at the moment, I use that range all the time. And a 90mm macro too.