let's see
GBC - 6 months or so after Pokemon R/B came out
GBA - Not sure. I still have it, it's the clear light purple (Glacier?) one. Probably pretty early on that one.
DS - Launch. Still have it, have not upgraded
N64 - DK64 bundle
GCN - Launch
Wii - Launch
360 - August 08, right before Rock Band 2 came out.
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HAIL THOMAS