You can't go wrong for price/money/quality with the 40D. It’s a great camera.
Having used Canon SLRs for 30 years, this does the Canon name well (but it isn't in the same league as the superb T-90 was in its day.)
Controls are a bit complicated but not overly so.
One thing that personally bugs me is the lack of a "snow" setting for White Balance, which seems an odd oversight, given all the other settings for WB. You have to create your own in the “Custom WB” menu.
Regarding FOCUS issues, which many have commented on, I agree that focus can be inconsistent. Part of the problem was my own transition to a DSLR from digital compact viewfinders (S-80, G4, G6) and not understanding the incredibly shallow depth of field that a DSLR has compared to compact cameras and film SLRs. My initial few hundred pictures were mostly either blurry from "too slow" a shutter speed (- I had thought 1/125 would be 'fast" enough- ) or out of focus/unsharp (- I had thought f5.6 was a reasonable DoF to get all of a face in focus.)
Regarding IMAGE QUALITY, when shooting outdoors in bright light at speeds of 1/500+ and f11+, the pictures are superb. This is where it really excels. It seems that for DLSRs, SS1/500 and f11 are the “new” equivalents of the old film SLR 1/60th and f5.6. (I bet that explains the great shots of the kites one of the reviewers commented on.)
For SHARPNESS, I learned through the forums that the standard default “sharpness” setting is actually rather “soft,” so by changing the default sharpness in “Picture Style” to a higher setting, the results are probably what most people would expect.
For FLASH SHOOTING, the default1/60th setting for the built-in flash/external flash also frequently yields blurry shots, so using the 580EXII strobe and changing the default 1/60th flash SS setting to the alternative default 1/250th SS with a bounce yields great flash shots. (Note to Canon: it would be good to have a 1/125th sync as well, not just the 1/60th or 1/250th options.)
Once I started doing that, my percentage of well-focused/non-blurry shots went way up.
But there are still some surprising inconsistencies and I'm not sure if it is the 40D or these kinds of DLSRs in general. Sometimes one has to shoot at 1/100 and f4.5, and that's when number of blurry/out of focus pictures increase on this camera, (but almost never on the compact cameras.)
FOCUSING: Changing the 9-point focus doesn't help much so leaving it on the center-point focus seems to yield the best, consistent results. Note to Canon: It would be better if you could also set pairs of focus points. Instead you are given the choice of “all” 9 points or just one of the 9. (If you are shooting a couple, for example, you need to be careful not to frame them so that the center focus shoots past them in the middle.)
LENS MANUAL FOCUS: Another peeve with Canon lenses used with this camera. When manually focusing with the old manual FD lenses, one could just turn the focus barrel all the way to the right until it stopped and you’d know that you were in focus at infinity. No way with the new EOS lenses! If you manually turn the barrel all the way right, you will not be in focus at infinity! Don’t know why. Infinity focus is at some point slightly before the maximum turn of the barrel. This makes it difficult under low light conditions, or when you know the object is at infinity (such as shooting to a stage or altar or the like from the audience) and don’t need the autofocus, you have to be really careful as you must manually refocus every shot in case the barrel has moved during handling. You can’t just flip it quickly to the maximum right. This inexplicable focusing requirement is very inconvenient on any lens you use with this (or any other Canon) camera.
HIGH ISO SETTINGS: Shooting at ISOs of 200, 400 and 800, and even 1600, yield pretty good quality photos, with low “grain” even at 800 and 1600, and very little purple fringing, so adjusting the ISO to compensate for the demands of a higher Ss and deeper DoF is, unlike with film SLRs, a very viable option.
No camera is perfect, and this is a great camera. despite some limitations. You need to grow into it, and then can be more confident that, personal incompetence aside, the camera will deliver good results. I also recommend looking at the topics listed in the forums. There’s a wealth of info on your specific camera and lens combo and situation. They helped me overcome a lot of initial frustration and improve my results.
So, I’m very pleased overall with my results and I would recommend a 40D to anyone (although I still pack my S-80 as a backup and for handling different situations, as well as when my arms get tired!)