Well... this may sound odd, but my favourite is TF Tripwire, I got from my grandmother around 1989 or 1990 - don't remember if I was 3 or 4 years old then...
Had him 'till today - now as I got many other figs, he's not playing any significant role in my dios, but it's one the "very basic" Joes I'd never sell. Or trade. Or anything.
He's quite well I must say, only a little paintwear and a broken crotch - thumbs and other stuff in great shape, maybe only not counting small elbow cracks, which are anyway sealed with epoxy glue. So, I got him for 17 or 18 years now. Brings back memories

Like Undertow and Ambush too

(my second and third figure. I bought Ambush myself, when I was 5

)
OK, enough, I could write a whoe lot of story on each my "very basic" Joe now

And I had about 20-30 of them as a child

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My weekly TOP5:
The sacrifice of innocence the hailing of the gun
My way was death and madness, now let the Tower come