Hello, and welcome.
1) I'm on my second 2.2 diesel in as many years, and I personally love the engine. As has been mentioned, you may notice it a little more on a cold day, but most people I drive in my car comment how it doesn't sound like any diesel they've ever heard, i.e. it's much quieter.
2) I've never had any issues with the look or function of any Honda key. At least it's all integrated now. Who remembers the last gen's seperate key and fob combo?
3) Having just done some waiting myself (though, not much compared to you!), I recommend the following; get hold of a brochure, so that you can lust over the images, and read the marketing blurb about your fantastic new car. I always do this when I'm waiting for a new car, and it certainly passes the time.
Also, read as many reviews as you can find for your model, and check the Wiki for any known issues. Forewarned is forearmed!
Most importantly, spend some time on Civinfo, and see what's what.
You've picked a fantastic car, with a fantastic user community and website.