hmm.. can't even remember what the first was... some 64 meg thing that fit in my PCI slots, was the first form of "SLI" I believe... was running in my 633mhz celeron at the time :P.
BBA X700Pro AGP
BBA X700Pro PCI-E
C3D X800GTO PCI-E ( currently own this, and I don't especially miss the 1800 or 1900)
GFX Cards owned - 5600,5700,x700pro,x800gto,x1800gto,x1900gt
GFX Cards I want -
7950GX2, X1950XT, ??R600??