Take maz's advice - don't whore the transitions - and for gods sake make sure the sound is off on the transitions...I once went in to give presentation on sexual health & condom distribution to Exec management team and had car 'whooshing' noises on the transitions....I didn't realise sound was on there because didn't have the sound on on the laptop I'd used to create the PP let me tell you - you only make a mistake like that once ...cue jokes about climaxes and roaring engines