I want to say that it was the Ultimate prize for 2010 and 2009. This link proves it:
On top of that, I'm willing to bet it will be the same as Club Nintendo where it will be the same prize every year. So it's more likely that ultimate will still be the ipod with all the other goodies.
Yeah, buying all the games that you would need to get to ultimate would be spending just as much if not more than the ipod itself. But, if you're buying the games anyway it's a nice bonus.
Considering the prize everyone is awaiting an announcement for is the 2010 prize, you're already losing your bet. The SE members program has only been around for 2 years now, and only the 2009 prizes have been awarded (which happened in 2010).
Also, why would they give out an iPod again? The vast majority of current ultimate members already got one last year, it wouldn't make sense to give them another. Also, Club Nintendo has given out different prizes for both years it has been active. Mario Hat was 2009, Crappy statue was 2010. Those aren't the same by any stretch.
It's likely that SE is waiting to announce the prizes when they actually have them in hand, unlike last year where they announced them 4 months before they even had the prizes day to go. Just be patient.