I'm in the market for one. I'm leaning toward buying a 4mp such as the Canon S4000 Elph. I am trying to determine whether it is necessary to buy a 4mp over a 3.2 when my only concern is the quality of 8x10 enlargements which I decide to print. Technically I know the 4mp will give me better results; but will the results be so clearly superior to the 3.2 mp ones?
I've read the reviews on various camera sites etc. but I'm looking for "real people" answers from fellow Fodorites!

The only way to really figure this out is to use that particular camera with all possible options and test the results.

With ours, the results were not what you'd expect.

Generally speaking, though, if you want to print 8x10's, the more the mp's the better.

Though, sometimes your printer and software can more than compensate.

I have a 3.2 megapixel Olympus Camedia 730 with 10X optical / 3X digital zoom. I've printed out and also had printed at the local camera store photos up to 8 X 10 and they've looked great. You won't get anything larger though. I usually print 4 X 6 and those are fantastic.

Ask at your camera store. They should have plenty of photos taken by each of their cameras and printed on different kinds of paper. You can compare them and decide what works for you.

I purchased a Pentax Optio 550 -5.0 MP in October. The shots are clean up to 16x20"prints. Excellent zoom; mic records voice and music, even at a distance; zoom and macro are superb. Slightly larger than the Canon Elph and lightweight. Uses SD card for memory. Upload via USB or using the Secure Digital card. Excellent camera for around $475. I would recommend you compare features against other 4 to 5 MP, emphasizing largest optical zoom if you take distant shots. I don't know why the Pentax Optio is frequently overlooked by digital camera purchasers. They are missing out on a good product.

Checking my favorite camera site it seems 3.2MP is enough for a 8x10 print assuming a 200DPI resolution on your printer. But if you ask me I would say more importantly than either 3 or 4MP is the rest of the camera. It doesn't help to have a 6MP camera if the optical system is pure crap or you get so much noise in the picture from a bad CCD chip that the picture is useless anyway...
So when you want to buy a camera, ask to test it in a camera shop, and get them to print out the picture for you. And completely ignore any digital zoom (that is a buzzword for more noise in your picture ). Optical zoom on the other hand is usually handy...

Cobos

This is a very difficult question because everyone has their own standards. What one person thinks of as a beautifully detailed enlargement might make another's teeth ache. I agree with the comment that, all things being equal, the more MPs the better. All cameras I'm familiar with have ways of not using their full resolution if, for example, you need to cram more images on to a memory card.

One important thing that hasn't been mentioned, though, is that you won't always want to enlarge the entire frame to 8X10 or whatever. Because it's now so easy to do on the computer, you'll find yourself cropping images and enlarging only a portion of the frame. So, if you want to enlarge say half of that 3.2 MP image, you're now only working with 1.6 MP, which brings me back to my original comment, which is that more is better.

I recently purchased the S400, by the way, to add to the G3 and S45 I already have. I haven't used it enough to comment much, other than to say it's one very neat package. Canon also seems to have excellent lenses and good image processing software (in the camera), which is also a factor in image quality.

Check out dpreview.com, if you haven't already.

The dpreview site mentioned above is your best bet for comparasion shopping. And as pointed out by others, the quality of the lens makes a huge difference. I have a 2mp Olympus, a 4mp Olympus and a 5mp Nikon. In some cases the 2mp Olympus provides the best results - even at 8x10. But that is a great camera, with a 10x zoom and an image stabalizer which most cameras don't have. Certainly in some situations the 5mp Nikon has the best results but not all (hand held in very low light that image stabalizer compensates for a lot of megapixels). The lens is extremely important.

So between a 3.2 and a 4mp camera I would make the decision based on the other factors. Other good sites to check are stevesdigicam and megapixel.net.

There should not be much diff in picture quality between 3 or 4 mp cameras. But I have used both the S400 and the 3 mp version elph as well, and the S400 takes much better pictures. I am used to using 35mm SLR's and am AMAZED at the picture quality the S400 gives. A great choice for travel- I took a S50 and S400, and always used the S400.

I just bought one in December--came down to the Elph or the Canon Powershot A80. Tried both and pictures are excellent. Finally ended up with the A80 as the Elph was too small for my hands. It is a great camera. I've done everything from the Costa Rican Cloud Forest at it's cloudiest, to rain forest night hikes, to sunny beaches in Florida, to indoor portraits--all have come out very well. I don't have much patience with learning intricacies of camera settings, but the preset selections on the A80 have worked fine.

Forgot to add that the A80, though larger than the Elph, is still small enough to easily fit into a jacket pocket--it's not much larger than the Elph, just enough so I can handle it easily. Your talking ounces in weight differences, not enough to notice unless you are really really weak.

You won't notice the difference between 3MP and 4MP. The differences between my own Canon S10 (2MP) and the S400, while noticeable, are not stunning.

Having said that: These days, I'd get the S-400 for travel (plus an extra battery). You'll end up taking it with you more often than a larger camera. It's dropped $100 in the last few months to make way for the S-500.

Note: The Canon A-70 has a unique "hi-resolution" Video Clip Mode.

I really appreciate everyone's responses. Like i said, reading the reviews by the "experts" is fine, but getting a number of opinions from a source that I trust (ie. posters on this board) is truly helpful.
I'm afraid buying a camera for me is like planning a trip...half of the fun is in the planning!Thanks again