Originally posted by Duchess64
"Will this set a precedent?"
Probably no more than King Edward VIII's abdication 'set a precedent'.
"Who is likely to be the next Pope?"
Has Las Vegas set the odds yet?
Edward VIII abdicated for very specific reasons, which were unlikely to be duplicated and which (by the moral standards of the time) were arguably disreputable. With this negative precedent, it's unlikely that a British monarch would abdicate, except in extreme circumstances.
A closer comparison to what Benedict has done (resigning because of old age) is the abdication of Wilhelmina, Queen of the Netherlands, in 1948. That did set a precedent and her two successors have similarly abdicated.
Actually, it may be that the reason no Pope has resigned for centuries is because previous abdications happened in dark circumstances or had negative consequences. Thus, when Celestine V "made the great refusal" (Dante's phrase) in 1294, he ushered in the reign of the notoriously corrupt Boniface VIII, while Gregory XII was humiliatingly obliged to abdicate in order to end the Western Schism. Those precedents had surrounded papal abdication with a aura of failure and menace. Now that Benedict's action has suggested that it's OK for a Pope to step down just because of age and failing health, I wouldn't be surprised if that became the norm.