I’d grab myself an original Pedro Flores Yo-Yo since I can outbid everyone :]
As for modern yoyos, I’ll grab everything in Hiroyuki Suzuki’s sOMEThING line. Especially the FIRMY, ANGLE, ANGLAM, and The V [the yet-to-be-released delrin yoyo]
Maybe a few yoyorecreation yoyos too.
And 10 pairs of Yomega Raiders/Fireballs modded to perfection.
I would purchase the remaining 8 white powdercoated addicts, so as to spite buck lynn. 
I’d go with either the Anglam, Code 2, Arctic Circle or Sleipnir.
Planning on getting a Code 2 soon though…
Nows your chance. 
Catch22
Overdrive Draupnir
Titanium Wide Angle Shutter
I mean… that was seven years ago lol
Tough choice, would have been able to answer this back in 2012 when this thread originally started… I obtained several yoyos over the years of varying types/sizes/material. Today, it would have to be something rare or discontinued (I wish I had checked out some of SPYY’s goods back when they were still around).
Oh, and maybe a One Drop Citizen 
I know, I just posted that to spite the guy who intended to spite me 7 years ago… I got 8 of em for sale. Lol
I got a great laugh out of this. Best necropost ever.