Between the potential/minor light-leak issue and the DPP issue, it sounds like there are two rumored reasons for a recall. If it ends up being the DPP issue, I wouldn't worry...you can just download that off of Canon's site. If its the light leak issue, that only seems to actually be a problem when photographing with the lens cap on (or, conversely, when your literally in the dark.) For normal use I don't think that will be a huge problem, however if you do a lot of low-light shooting or astrophotography, you might want to hold off on a 5D III and see if they fix the light leak issue.
Personally, this is why I wait to buy anything new...there is usually a round of recalls and/or firmware updates before a complex new product released under the strong heat of competition is solid and really ready for prime time.