Don't get me wrong, I'm not saying it doesn't matter...it needs to inspire etc...how many times have you thought I don't sound quite right and it throws you off? Totally happened to me many times. In the same way as sound via IEM's drives me nuts....but I've also accepted that my sound won't be perfect and as long as I can pull my pinch harmonics I'm happy
My ego needs constant feeding...I was also a child of the 80's....a pattern ? Ha!
I need it to sound good. Somehow, when things sound good it becomes easier to play. But there's a tipping point of worth. My rig is complex enough now that I use a double sided 10U rack case. Add two guitars, do I need to have a cabinet for that extra few percent?
For me, no. I'm also the singer so my vocal monitoring is way more important. I've played with seriously good musicians that finish a great gig and comment how terrible the sound was for them on stage yet gave nothing away for the whole performance. But I've also watched players making all kinds of demands on the sound man, or playing with knobs and settings throughout a show in their quest for perfect sound, to the point of it becoming a distraction for the audience.
A couple of years back I experienced a band setting up in a pub. I'd seen the guitarist's Friedman and really nice Les Paul. As the rest were setting up, he was cranking out classic riffs and I was massively impressed by the tones. Really top class sound. But not only did he carry on wanking away for about 15 minutes to the clear annoyance of the customers, when the band started playing properly, they didn't sound that good. Nothing major, but a let down from the guitar sound alone.
It made me consider just how important that great sound is and whether I'm too focused on it. Would I rather be like the bass player that plugs into a backline bass amp, shrugs his shoulders and says 'Good enough for me' or the guy fiddling his way through the show, desperately trying to find the missing mojo. Sadly I've been that guy and I regret it rather a lot.....
Again, not saying that great sound isn't important but it's definitely worth putting it into perspective.