With an ISO 100 setting, the camera reports the following amount of pictures for a 512MB CF card:

Raw: 69
JPG Large/Fine: 157
JPG Medium/Fine: 267
JPG Small/Fine: 355

In addition, the amount of pictures you can take decreases if you use higher ISO settings. This is because the amount of noise in the pictures increases with increasing ISO and therefore the JPG compression algorhythm will have to deal with more detail in the picture, which makes them larger.

I usually shoot JPG on Large/Fine, and for my personal shooting habits, a 512MB card is the minimum in size.

Luckily there are devices out there that will allow you to download the CF contents to another medium and continue shooting. These could be a Notebook PC (with a compact flash adapter/card reader), an X's-Drive II (http://www.vosonic.com/index.php?php_mode=spec&php_itemid=11) or an Archos Jukebox Multimedia plus Card Reader (http://www.archos.com/products/prw_500561.html)

Note: this is not a comprehensive list, there are definitely more solutions out there. Another solution would be to get more CF cards :)

(nubui)