As far as their larger products are concerned, I think that Oracle is a much better fit for Sun than IBM was. Obviously there will be some overlaps in technologies (MySQL vs. Oracle being the big one) but on the whole, I think these companies match together pretty well.
Are there any other huge overlaps in technologies (other than the obvious MySQL/Oracle)?
Definitely not as big as MySQL/Oracle, but one that I'm wondering most about is their open-source app server Glassfish. A big part of Oracle's BEA acquisition was bolstering their middleware suite (with WebLogic, et al.). Will Glassfish development continue? I hope so...
Are there any other huge overlaps in technologies (other than the obvious MySQL/Oracle)?