The empty template in my presentation app SlideMagic uses pretty much the same layout as my bespoke work in PowerPoint/Keynote for clients:
Big slide headline that can run over 2 lines (I like elaborate titles, similar to newspaper headings), without any graphical elements (lines, banners, logos)
- Small logo in the bottom right, I compromise here and give in to most companies insisting that the audience should be reminded to whom they are listening on every page. Many clients want to move that logo left, which creates a graphical imbalance: the bottom right logo balances the weight of the left-aligned title in the top left. Also, a logo at the left creates problems with footnotes.