Re: Digital Camera Lenses
You don't need a digital-specific lens for a DSLR - I don't own any and have taken 10k+ images in the last year with few problems.
There's a good article about this subject in this month's Digital Photo Pro magazine. Basically what happens is that there's a glass "filter" in front of the digital sensor. In some cases, light may reflect off the sensor, back onto the lens and give you ghosting and flare problems. I've had it happen a few times with bright light sources in the frame, and especially with my Nikon 20-35 zoom. One thing that helped was a thorough cleaning of that lens (Eclipse solution) although I never had anywhere near as much of a problem shooting with the sun in the frame on film! Of course any wide angle, especially a wide zoom will flare with the sun in the frame...
Your 28-200 will work fine on the D70 but you might want something wider because of the smaller sensor. It will take the kit lens for this camera (18mm on the wide end) to give you the same 28mm perspective. There are also other options, but you might want a wider lens than what you have because of this.