^: Well, if it has to be the past, and it also is a view-only experience, I'd want to pick something I could use for monetary gain upon return. Say viewing some famous but poorly recorded event. Examples springing to mind... JFK's or MLK's assassinations, OJ Simpson's wife's murder, especially if I could record video or holographic footage.
<: Maybe something less gruesome could also fit my criteria... a bidding war on what data to get might be a good idea.
V: If you file taxes, do you use software, a preparation firm, or pen and 1040/etc? (If you don't, how do your parents/roomies/etc?)