OK, first a pet peeve - you have a pilot's certificate. Licenses are used for fishing, hunting, driving, etc.
There, I feel better. Anyway, as far as the DA40 vs. the 182. I instruct in both of them and am qualified to teach G1000. Both installations are essentially alike, with the exception of the circuit breakers and the location of the emergency gyros. Cessna didn't use pullable breakers and Diamond installed the gyros just below the glareshield as opposed to the bottom of the panel.
From the standpoint of flight characteristics, they're both great airplanes. The biggest difference is that slowing down the DA40 is a bit trickier because it's a very slick design. Simply put, you can't charge into the pattern like you can with a Cessna (or a Piper) and expect to slow down to a reasonable speed easily. You need to plan for the pattern a few miles out, but then you should do that with any airplane. Having said that, there is a myth that the DA40 has to be flown in a very wide pattern because of it's clean design. If flown at the proper speeds, you can safely fly it in the same size pattern as the Cessna. And don't let the whole yoke vs. stick debate throw you. Other than pilots'egos, at our level there really isn't any difference (and, by the way, the P-38 was a great fighter and it had a yoke).
Composite vs. Aluminum? I dunno. The DA40's and C1's I've seen in training are holding up just as well as the Cessna products. I've taken tours of both factories and have been impressed with the workmanship in both. I trust both airplanes, else I wouldn't fly in them.
So now it's down to creature comfort, payload, and style, at least as far as I'm concerned. Quite honestly, the DA40 wins on style points. It looks cool and like it's going 120 knots just sitting on the ramp. On the flip side, though, I'm inside the airplane when I'm flying, and there usually aren't girls to impress as I fly by anyway (besides, my wife frowns on that kind of behavior). I think that the Cessna is a bit more comfortable, particularly for the rear-seaters, and some folks don't like climbing on a wing to get in a plane. At 72.5" with long legs, the DA40 does fit me, but the rudder pedals are almost full forward (the FBO joke at my home base is seeing me scrunch into one after one of our female instructors has been on the right side - I can't wait to get to the T-handle), and there is pretty tight clearance on the headphone band.
Reviewing my musings above, I can see we're in the same quandry. If I had the cash, I'd buy both, because I see them as having slightly different missions. If I wanted to go with my wife and take the dogs somewhere, I'd use the DA40. If I wanted to take another couple or carry some camping gear, the 182 wins due to it's higher payload and the ability to trade off some fuel and still have a decent range of action. Unfortunately, we don't have that kind of money, but we are very seriously in the market for an airplane to put on lease-back, looking at about a year out (there's Diamond dealer in my part of the midwest that will recognize my name if he reads these posts - like I said four years ago, we're on a five year plan).
So, I, for one, don't have an answer for you. I've told both manufacturers at OSH that they're toe-to-toe as far as this consumer is concerned. I have no influence on the manufacturers as an individual, but it would be great, in my opinion, if one or the other would come up with a knock-out punch. In the meantime, I suggest you consider range, payload (and if you have small children, remember the number of bodies may not change, but the weight you carry will), and the overall mission of the airplane. And don't forget, there may be times that whatever you buy, you may not have the right aircraft anyway - I fully envision times when I'm going to rent a Cherokee Six/Saratoga even when we own an aircraft - just like we rent a van to haul bulky stuff around.
One last point to consider - the DA40 might be a bit unusual to a lot of FBO's if you need work away from home base. Having said that, though, it'll be the engine that will most likely need loving care, and they're ubiquitous enough that it shouldn't matter. Again, I know you have tough decision, ''cause that's where we're at. In our case, it may just rest on who can deliver an airplane and financing first.
Thank you for your input. What do you think about resale value of the airplanes. I would think Cessna would have a better resale, because of the larger demographic of pilots who would fly it. What do you think? Also, the FBO's we would fly to as I said before are both Diamond dealers. Is that something I should take into consideration?
I don't know if this has to do with the amount sold, but a Cessna 182 from 2004 is generally about 1/4 of what it would cost brand new.
Diamond DA40s are EXTREMELY hard to find on the used market (must be a good plane).
Cirrus SR22s (the best selling new plane for the past 7+ years) are one of the easiest airplanes to find on the used market.
So I hope you bought the right plane for you!