I’m on a 2013 home-built AMD FX-6300 six-core processor, Radeon HD7770, 16GB ram and 3 physical hard drives all 7200rpm (not yet made the leap to SSD on my desktop!): 1 shared between Linux and Win10, another for all audio recordings and final one for all my sample instruments. For audio interfaces I’m currently using an M-Audio Audiophile 192 and some of the Behringer UMC series depending on channel count. I have a Creek OBH-11 powering AKG K701s and Beyerdynamic DT880 Pros and KEF Q100 speakers (odd choice for monitors but I trust them for what I do!).
For platform I’m currently on antiX 17 and Ardour 5.12 but will shortly install version 19 fresh as I await Ardour 6 (can hardly contain myself for the latency compensation stuff!). As I’ve mentioned on other threads bare-bones efficient OS has made the biggest difference for me along with using Liquorix as my low-latency kernel. Not a single x-run to speak of since I switched to this setup and easily achieve your desired sub 10ms latency numbers.
I have an Ideapad S540 winging its way to me with 8th gen core i5, 12GB ram and a 256GB SSD which I fully expect to run my classical on-location stuff very well. I’ve yet to figure out if Linux runs well on it but, honestly, for now it will be there to run a Pyramix native install coupled with the MixPre 6 as a USB interface. Linux will follow in good time. The thing I struggle with for laptops+Linux is always the battery drain but, to be fair, I haven’t scientifically tested this in a long time and I assume at least some progress has been made.
To answer your question “What’s your rig?” in the most helpful way I can, I would echo @alexmitchellmus in saying that my 2013 custom build is still holding up very well. In fact, it feels extremely zippy in both Win10 and all Linux distros I throw at it. At no point for anything do I think my computer feels old.
If I were buying right now, I’d pick up a middle-of-the-road Dell/Lenovo desktop or laptop and a Focusrite Scarlett of some kind (or your RME Babyface Pro if you consider the preamps to be that much better) and have fun making good music! It would be great to have separate drives for system and recording if you can. An even cheaper (and satisfying) way is to build your own using pcpartpicker.com though having had good luck with both Dell and Lenovo, it would be a close call for my own future machine. As much as I drool over the Sweetwater Creation Station stuff, it seems a little overkill…Though if money is no object, you’d also get some of the best support in the business.