Am i wasting the cameras potential

Having just bought the 20d i have tried the image sizes and although the camera is capable of large files [3504 x 2336 Large fine setting] i have also tried it on medium fine settings [2544x1696]and the pictures are still bigger than you would need in real terms .
By doing this i am getting more photos on my CF Card and still large files but am i ruining the reason for this camera,all opinions welcome please.
P.S i don't print larger than A4 and i am not a professional,just a serious hobby for fun.

Do whatever suits you... If at a later stage you decide you want to print larger pictures, you have that capability.

By using a smaller image size, you are disregarding some pixels. I'm not sure whether it just misses out every 3rd/4th/5th pixel (for example, not a real world thing), or whether it downsizes the image after taking it at full res. The first one would give better IQ, but both should be fine.

If you shoot at lower resolution, all your doing is reducing the information you have from the scene. You need to remember that in the DSLR market, resolution isn't everything. Its nice to have 8Mpixels, but you use the camera for the features, not the resolution. If you are really worried, just get another memory card. I have 2x1GB, and can fit 220 Large fine jpegs on each (ish). Memorys pretty cheap nowadays. It depends whether you feel that the extra resolution is worth and extra $40.

I'm sure the medium or large resolution jpg would be fine for the size I generally print too, but shooting raw allows me to save the shots that might otherwise be trashed. There is just the extra little bit of post processing adjustment available in raw that just doesn't work as well in jpg.

The unwritten rule is to shoot as big an image file as you can with the memory you have. If you shoot small image files you have reduced your ability to crop and still have a good looking image.

Exactly...you expand your capabilities, even when you dont print above A4, by taking the most amount of information with every shot. Enjoy your new 20D, its a great camera.

Trumper - you never know when you might want to crop something out of an image and blow it up. You would probably want maximum resolution for that.

I assume you are shooting only in .JPG mode. There are so many benefits to shooting in RAW mode that it's hard to include them all in a single post. The thing that turned me onto using RAW, though, is the simplicity of changing the "white balance" - color compensation for shooting in different types of light. If you had your camera set for "daylight" for example, and shot some indoor photos with ordinary incandescent bulbs, your images would have a yellow-orange cast to them. Fixing this when all you have is .JPG files is often very difficult. With RAW files, you merely re-choose the white balance selection when converting RAW to a usable format - as easily as turning the dial on your camera.

Using RAW files does require you to convert them to some other form for editing. What I do, though, is shoot RAW plus Large .JPG all the time. That way, I can look at the .JPG images with no post-processing, and use the RAW file as a "digital negative" to create a .PSC file for editing, etc. The only requirement is that I need more CF card space for the shooting that I do. That's cheap, though.

.JPG files have a characteristic that you should understand as well. They are all compressed, which reduces quality from the start. Each time you open and then save a .JPG file, you further reduce the quality. In other words, if you want to do any significant editing, you should NOT be starting with a .JPG file format.

Trumper, Yes Med will work just as good as large if you don't plan on alot of cropping. I had a 3mp cam that would print beautiful 8x10s so going to Medium here will not hurt you and it will give you more space on your card.

It's safest to always shoot in the best quality and largest resolution you can. You never know when you'll need to crop fairly drastically, or want to make that big enlargement for your living room. If you choose a resolution based on what you "usually" need, when you need to push the limits, you'll regret it. Memory's cheap, and shooting Large Fine JPEG will still get you 300 or so shots per 1 GB card, as opposed to 500 in Medium Fine, That's a lot of photos to sort through after a day's shooting.

It is illogical to use any other than highest quality settings for your photos in the long run. Sometimes you may be running out of free CF space and be forced to use less than maximum, but otherwise, on a normal, sunny, idle day, to shoot your cat/dog/birds in the backyard and using 4 megapixels just because you apparently don't print big? Let me ask you something then.. do you make photos for today and tomorrow? I do them for time measured in decades rather than days, and then, I know I WILL appreciate every bit of information that was retained in that RAW file I took.

While it is nice to have all your photos in the highest resolution possible 'just in case', you also have to remember that a lot of people are still shooting with 4mp cameras like the 1d and they're doing just fine. Use whatever resolution you want, you're not wasting the potential of the camera, but you are limiting the possibilities with your images.

i say unless storage is an issue, use the highest resolution. you never know when you might want to crop an image and print it. the higher resolution will give you more flexibility.

storage is THE ONLY drawback

I believe the 4mp photo from the 1d, is nearly the same in quality to the of a 6 mp camera, because of the better sensor. But even then, you want to use your camera at a higher quality level.

A 1 gig card should get you near 300 photos on jpg fine large.

I agree with this. my 16.7mp camera makes the best 4x6 pics in town!