Very interesting thread :D
A big plus from me on the difference that picks make - never really noticed before, but I've been doing some recording over the last few weeks and I've been switching picks (on the same guitar and amp settings) to get different tones for different overdubs.
I'm not sure on the "is tone-in-the-fingers true/false?" debate, but I can add to it slightly:
I use modellers now, not amps (so take this with a pinch of salt), but I find that with all amp model types and all of my guitars I tend to reach for the same basic "my-tone". And I usually reach it - humbuckers, single-coils, through Marshall/Fender/etc... and I always sound pretty much like me.
The differences are usually to do with how clean or not I want it, whether I'm playing rock n roll, or blues, or rock, or something else. Also, sometimes I want a distinctive "that's a strat!" (or whatever) sound - you kinda need to pick up the strat for that if you've got one... (however, I can make my MQ'd Explorer sound surprisingly close enough, or even my Mule'd Love Rock...)
Overall, in the past 12 months, "my tone" seems to be something that is a lot more "fixed" than I ever imagined before I started buying all these different guitars and pickups (and discovered amp modelling).
BUT - to possibly contradict everything I've just said: I still find if I play the Love Rock exclusively for a few days, it takes me several hours to get into a telecaster or strat (and vice versa) afterwards. I'm talking about the sounds I get out of the speakers, not the feel of the neck etc... Now, is that to do with the inherent "tone" of the beasts, or is it because I'm learning to deal with a more/less distorted sound?? Who knows? (Or cares :lol:)
Finally, another big plus to what someone else said earlier (38th I think) - when you think you've got your settings, roll everything back just a tad... usually sounds loads better! (applies to guitar controls, amp controls, fancy eq/effects in the mix, everything)