The Canon 20D don't come from Canon with a memory card though some dealers put together kits that do include the memory card. The 20D uses the CF (compact flash) type cards. I would not buy the canon brand though I have not heard anything bad about them. Canon does not make their own cards it is just made for them to their specs. The two most popular brands with photographers are Sandisk and Lexar. I personally use Sandisk Ultra II's and Sandisk Extreme III's and have had no problems with them. You can get the Ultra II 1gb card at B&H for $52.95 plus shipping. the Extreme III's are 59.95. + S&H. When I bought my Extreme III card it came with their RescuePro software that is used to help recover images from corrupt cards, or even images that have been deleted if you have not written new files over them. I have never had need to use the software though. I do not use the standard (cheaper) cards even from Sandisk except in my wifes point & shoot Canon A540.
The CF card is all you will have to have to make photos with the 20D other than whatever lens you will need for you work of course. Though if you are like me you will find a lot of things that you just have to have. I would suggest an external flash instead of using the pop up flash. I am still using the old Sunpak 555 I used with my film camera. Word of warning though, some older flashes have trigger voltages higher than the 6V or less suggested (required) for all digital and some film cameras to keep from damageing the electronics. If you were planing to use an older flash if you PM me I will tell you how to test the trigger voltage on your flash. Its easer than it sounds like it would be.
