I had finally decided on what watch should be my first chronograph...

Two words: value retention

Well, even at retail they're not exactly on the same price range.

I’ll throw a spanner in the works 😉 - how about a Mk II? Automatic, co-axial with column wheel, 100m water resistance, 52 hours reserve, chronograph, cool:

Do you have a price range for more pointed suggestions? Datograph and SM300 are not in the same zip code

It looks great but the big hands hide the smaller chronographs and make it harder to see them clearly. For me the Speedy Racing with the white dial does it for me. I love the movement,and like that its less cluttered with two dials vs 3.

I’m new to Omega, but have had many others, including Tudor, and their Chronographs May be worth considering. I agree with the comments above about the Seamaster being too busy. I’ve never been a fan. I have a later tritium dial Speedmaster and I love it, but for everyday use, particularly around water, it doesn’t work!! There’s some good alternatives being suggested here.

I see a lot of people pointing out the price difference in some of the watches I've mentioned.
Price isn't really the deciding factor here, nor is resell value as I tend to keep my pieces. Anything south of what's equivalent to $20k (I live in Europe) is up for discussion. However, seeing as i'm going for a watch that will be used for it's sportiness, I find it hard to justify anything over $15k. That being said, I enjoy keeping my money for myself as much as the next guy, so I'm far from against saving a penny or two (hence the Speedmaster and Seamaster I'm looking at).

I do like the Speedmaster Racing as well, and I'd get the same 9900 that's in the SMP300. Maybe that's a good middle ground. I'm just afraid of regretting getting a Speedmaster that isn't a moon watch.

While we're on the 9900: Am I correct in understanding that the minute hands on the chronograph floats between minute marks instead of jumps, like on e.g. the 1861?

All the input so far has been great, and I enjoy people coming up with alternatives that might fit my need. You guys aren't exactly making my choice easier, but I think in this case that's not necessarily a bad thing. Maybe I should just realize that I need some more time to make my decision. It's not like I'm walking around wondering what time it is until I get my hands on a new watch.

Once you get a speedmaster, it'll most likely not be your last.

The choice is simple, what do you plan to do with your watch, what will you be doing with it? You intimated that the watch will be worn around, on and even in water, if this is the case the Seamaster or one of the alternatives mentioned by others would be the way to go.

The Speedmaster is robust enough to do most things but it only has a 50m depth rating, so whilst this is sufficient for most people splashing around in the pool or some gentle swimming in the sea it is not really an underwater watch.

So buy the watch that will suit your lifestyle best.

Or, do as I have done and buy the Speedmaster and a Seamaster (standard not chronograph), that way your collection is beautifully balanced.