Odaiba's true translation should be “attractions” because this is where all the museums, theme parks and recreational areas are! You can easily spend a couple days going through all the museums and theme parks, which makes it the prime place for tour...
Odaiba isn't first on my list for good eats, but with all of the new developments, like the Toyosu fish market, Senkyaku Banrai, and more, there are more and more restaurants popping up in the area.
While you aren't going to find your souvenirs in Odaiba (outside of museum gift shops), there are a couple great malls and shopping centers for you to visit and leisurely shop through!