Think I've decided...
First of all, I've let go of the idea of the Novation SL MK3 and Ableton. It's true that the integration is second to none, but on the other hand, I'm a novice and I don't even understand half of what the controls do and Ableton, after having played with the trial for some time, still feels a bit alien to me.
I've dabbled with Garageband so I'm going to stick to that, and most likely upgrade to Logic Pro X a bit later on.
As for MIDI controllers, I've been comparing Arturia and Native Instruments. The Keylab MK2 is a nice piece of kit, and the included software is certainly an incentive to buy a Keylab.
Both Arturia and NI have pretty compelling software but for the moment, I have a small preference for Native Instrumets offerings.
So I'll probably go for NI.
However, like I said about the Novation, I don't need too much 'whizz bang' and so I think the A-series will suffice for me. The S-series have those lovely displays and a better keybed (although because it is Fatar, I've heard comments of it being a bit noisy, something all Fatar keybeds suffer from, apparently, but that's not why I won't get the S-series. The displays, the light guide, all very nice, but that's to increase workflow basically, and ultimately, I don't care about workflow and one big computer screen will do just nicely, everything's there. Also, the A-series are said to have a very good semi-weighted keybed for the price range they're in, and certainly a whole lot better than Arturia's Essential range. Let's be honest, it's not for playing Chopin, but to mess around with. I'm also going to add a Maschine Mikro MK3, gives me something else to play with and the pads will come in handy for the stuff i want to do. All in all, a nice package, and very affordable.
However, there's still a very small chance I might get the Keylab MK2 instead, but it's more a case of comparing their software offerings some more.
As for the 88 key board, I was thinking Korg D1. Love the RH3. But then I started looking at some of the competition, like digital pianos which I can also use as a controller. Casio PX-S1000, looks nice, but ultimately, not the best option. Yamaha P125, an extremely popular model, seemed like a good option as well. The GHS is not the best action, but come to think of it, I don't really need an ultra realistic action just to have some fun with. So the action of the P125 would do nicely. More importantly, same length as the D1 so it will fit in my 'studio'.
Ultimately, though, that GHS action is also in the MX88, which was going to be my first choice for a 'fun' board. So I took another look, and didn't have to think long. The MX88 is highly likely. More iimportantly, though, also the same length as the D1, so it will fit in my 'studio', although it's a fair bit deeper, but it's the length that's more of a problem, rather than the depth.
That way, I can hook everything up to my Mac and my DAW, and still have a short fun jam with the MX and FM Essentials when I feel the need. Best of both worlds, or something like that.
And because I'll have the 88 keys of the MX to play with, I don't really need a 61 key controller so I'll be going for the KK A49, bit more free space on my desk, too...
I've got someone coming for the MP11SE next Wednesday so I assume I'll be ordering the new kit around the end of next week. Exciting times