If you go into modular, I highly recommend starting with a single manufacturer system. Semi modular is good this way too. If you buy by the module, focus on a single sound source with lots of control or utility modules first. I also recommend avoiding multifunction modules or those with unlabelled shift functions.
Software modular gives you an idea about patching but not the joy of hands on control.
Agree on this, although I love Three Sisters and I respect the hell out of Trent.
That said, if I was starting today knowing what I know now, I might go for a full NLC rack. That stuff is fun with a capital F U.
ahem leftmost centimetre of 0-coast ahem
Iāve got two racks of modules sat in the studio and not touched in over a year. I just use softube modular now for when I want some bleeps and bloops. I find modular a massive distraction and energy and financial black hole. Itās massively over rated IMHO. If you want to whet your appetite, ask yourself if youāre getting it to just tinker and play with or if you want to actually make music or do sound design with a setup. Just wiggling knobs and making squonks is totally cool, my day job is a sound designer though, and I find it overly complicated and frustrating. Like others say, try VCV or softube. Software route is fine for generative patches that play themselves. Otherwise having lots of modules you can just play and perform and express yourself is quite fun, just for me, the experience was more fun than the actual sonic results, which was always a bit lacking.
came here to say vcv rack, but i see thatās been covered. i learned everything i know about synthesis and eurorack modular from omri cohenās tutorial videos and the free version of the old vcv rack with only free plugins
its perfect
but semi modulars always feel kind of half-assed. iād go with something cheap like a cre8 case or the behringer go case and some basics
eurorack is normie gear now. iām seeing more and more people going back to fully built instruments as a way to start making music again
+1 for VCV rack if you want to try without buying anything.
Reaktor 6 is great as well if you own the Komplete thing or already have it, the Block part of it is what gave me the will to buy actual hardware.
About semi-modular iād say the most modular minded of all would be the 0-Coast, here is video i made about it telling how much I like it 
Has it? Didnāt know that!
Transistor based low-pass gate DYNAMICS
Got to test this further!
Also maybe find someone local to you willing to let you twiddle their knobs! Even a small system can be fun to explore in real life, if you donāt have a good shop nearby im sure you have a friendly Elektronaut or similar!
Iāve got enough spares to put a second rack together you could jam with in the corner if you happen to be in the south of the UK 
This is my only intention (for now)
Omri is great! For everyone mentioning VCV: I have tried it and really liked it. But the physical aspect of twisting knobs was greatly missed. Also the fact that it is one action at a time on touchscreen, made it feel not interactive enough.
Thx for all the advice and ideas so far!
I have a colleague that is heavily into modular. Maybe I should get him coffee more often.
Youāre probably a good candidate for Modular Addicts Anonymous. Iād definitely go for a semi-modā¦maybe even try out a full day with your friends system, and if goes well, just dive straight in (slowly).
I tried making it work with a couple semi-mods before accepting that I wouldnāt be happy with less than the full mod. Would have saved me some time had I realized that sooner.
I donāt think you will be disappointed by just jumping in the modular journey. What youāre longing for is exactly what you get, long hours of exploring and totally lost in time: what you get is interesting for the human behind the knobs and spaghetti .Others will mostly listen en watch and wonder what al that noises got to do with music. Donāt expect to get productive in a way that delivers tracks that sell big time but itās exactly the opposite: itās a expensive but very rewarding fun experience if you just want to noodle around. Vcv rack gives a taste of it but touching and patching is another level
Great video (also love your Tracker-stuff)! When it comes to modular, the Make Noise stuff has a big draw for me, because it is pretty non-standard but in a good way. Have been looking at a black and gold shared system too, but they are very hard to get. And I would have to save up some more and sell some other gear.
Either way the 0-Coast or a modular system, I would probably want to use it with a Keystep and/or OT I already own.
If you can find a used Microvolt 3900 by Pittsburgh Modular, you canāt go wrong with that. It is both west and east coast, has uncommon features such as a function generator, an analog sine wave, you can can boost any signal even audio one to modulate a lot of parameters. The filter is gorgeous but you can switch it to an unstable mode if you want some grit.
Itās layout is also less esoteric than the o coast which makes life simpler, it has a clock divider, step sequencer, arpegiator, a pseudo random gate generator etc.
Apart from some wobbly knobs, and the fact it only has one oscillator , this synth is to my opinion a masterpiece.
Edit : And being deep enough, I never wanted to go full modular because of it. I just got a Dfam to complement it, and itās been endless fun and experimenting since then.
I believe the latter assertion (although the āmusicā in it kinda proves my point), but for example there isnāt one shop in my town where I can buy eurorack.
0 coast feels like a well designed mini modular system. Highly recommended
Since DFAM/0coast/VCV/SubH have been mentioned I will say Bitwig Studio. Unless it must be hardware.
The entire DAW is essentially a synth and everything can be modulated. This is just icing on the cake on top of The GRID (Poly/Note/FX)
But I would say +1 to 0coast. DFAM is great but the 0 is really modular in spirit
I have tried Bitwig in demo mode, but I have such a muscle memory for Ableton that it just annoyed the hell out of me. Thatās not Bitwigs fault tho, also happened to me with Logic, but couldnāt get passed that. Also I found the interface really cluttered.
The 0-Coast seems to be the top favourite with you lot, so that is a really serious contender.
The modular thing seems to be different for everyone. My friend and I got into modular last year together, and his system is completely different from mine. If you go with Make Noise, I doubt you will be disappointed. ALM is another great choice. Those two companies are the basis of my system. Intellijel, Make noise and ALM are my favorite. And of course Plaits.
But, like I said, there are many paths and many destinations.