I've always wanted to have an A1200, which I now have, so that dream has come true :-). I'm not much into retrosystems other than the Amiga, so I wouldn't think I'd really like to have something else. I do have a pretty good looking C64 though.
But if money would be no expense, I would love to have the three great bigbox Amiga's (A2k, A3k, A4k), in mint condition and well expanded (060's, gfx cards etc.) sitting next to eachother on my desk. Man, that would be a sight :-D