I’ll say it again…for me it’s PATCH BAYS! Hands down.
For work flow alone it has been a game changer. Just makes me a happier person.
But also just for opening my head up to ideas that I probably wouldn’t have thought of. Bussing out “nuked” Distressors and then using a fader to blend in dry/wet for example. It’s a sound (when on its own) is too much. But blended in…sounds awesome. Or the same goes for adding cool guitar pedals to a track after the fact.
I can’t downplay the importance patch bays had on me in that respect. Before I got them I obsessed about everything being AS IS on the way in. To the point where I would re-record tracks constantly when I got an idea of how to tweak them. Silly…but that’s how I rolled for years.
Beyond patch bays…lately I’d say starting on Ableton Live has been equally profound for me. Having used Logic Pro for the last ten years. Logic is still superior in the editing side of tracking I’d say. But as far as being creative with song form, early development of the mix, Ableton is light years ahead. I was doing things within days that took me years to even think about in Logic. But again…that’s just how I thought about recording. Everything was premeditated and refined to the point of slight strangulation before I had even hit the record button once.
As far as gear ah ha’s…my favorite is finding just the right piece for each instrument/track. Having the gear is one thing, but knowing when to use it/when not is really the thing.
When I got my first Distressor I WAY overused it. Put it in every track on every song. Haha. It sounded TERRIBLE.
So I guess restraint is just as important. At least until you end up spending ALL OF YOUR MONEY by have 2-3 gear choices instead of just one. Lesson being, it’s better to have no effect on something sometimes rather than to have the same effect on everything. Seems obvious. But I think most people make this mistake when they get their first nice pieces of outboard. But the same definitely goes for plugins. In fact I’d say much MORE SO. To me those things get old real fast and only sound interesting when used here and there for a little variety to make up for your current lack of a Neve 1073 or a LA-2A. 
I will say, the importance of a good mic pre/DI in the age of the DAW is often overlooked. Most people seem to take the “fix it in post” mentality. Plugins can do a lot. But I still think the technology when it comes to mic pres is NOT there. I much prefer the sound of even a so so mic pre to a top of the line plugin mic pre.
Plugin EQs and Compressors get pretty close. Close enough that I sometimes hear the difference from one track to another and wonder what I’m blowing my money on. But…you then take that track and spread it across the entire song with 30+ tracks and hear the difference between one done with ALL plugins and one with ALL analog/outboard…it’s night and day. Doesn’t mean it’s not still good or bad music because of how it was recorded/mixed. But for anybody that is a tone geek, it makes a difference. But having that initial sound of a good mic pre on your track ALWAYS is the biggest factor. I don’t skimp on them. I don’t spend all this money on my beloved instruments only to have some plugin muck up how it sounds going into the box.
