Fran, The WA enabled - Write Acceleration technology that speeds up the transfer from the camera to the card.
The D-70 has the WA - Write Acceleration technology built in to the camera, according to Lexar is what helps speed up the transfer by up to 23% as compared to the same card without WA, say a 40x W/WA vs. a 40x card
Here's an explanation from Lexar.com on the 40x and 80x factors - the multiplier speed rating
Lexar CompactFlash cards are individually speed-rated so you know the minimum sustained write speed capability of the card. We use the same rating system used by the CD-Rom industry, where data transfers at a rate of 1X equals 150 kilobytes (KB) per second. And the higher the speed rating, the faster your camera can write images to the memory card.
As far as which one? I can not find any info from Nikon on how fast the D-70 is capable of writing to the card. I think you would be safe buying a 1gb 40x card, that will hold about 320 pictures. Later if you think you need more, you can go larger or faster, The prices will most likley be much cheaper a year from now anyway. The 512mb card I bought a year and a half ago was $95.00 after hunting for a decent price.
Here is a capacity chart
http://lexar.com/digfilm/capacity_chart.html You will probably want to shoot in .jpeg mode, you can then choose a size and a quality that fits your needs.
Bob,I think it's a good card, your camera is about 8mp If memory serves me, If you are shooting at full size you are transferring even larger files than a D-70
