Which Would Have a Greater ROI?

I was thinking a bit about give aways and whatnot at events and I got to thinking, which would provide a better return, in terms of goodwill and other maybe more “tangible” returns in our Social Media space (links, etc.)..I was thinking like would someone giving away a flip camera be better then sponsoring the food at a meetup? Does the return on either slide to one side or the other depending on the size and/or type of the event? Also would the type of people at the event change it?.For example if I were to give away a flip camera at the monthly meetup I attend in London be better then doing the same at a conference like PAB. Were talking 10 people at the meetup to 100 people at the conference. And how about the fact that I know maybe 50% at PAB, and most to a lesser degree then the 100% of people at the monthly meetup. What if it was a Sanyo Xacti camera instead of a flip ($800 vs $150)?.Any thoughts?.

Note: I’ve never made  money from referring to any other these products or site, I just own both the cameras and highly recommend them and like both PAB and the MeetUp. Although if Pure Digital or Sanyo want to send me new gear I’d be game!!!