Although many people cannot accept Tomiki's Aikido with a competition flavour, this style is practised a lot in the USA. If you like atemi waza, you will find alot of atemi in this style especially during randori. Atemi is used to throw someone or to create an opening for other techniques. Tomiki Aikido is also called Shodokan Aikido.
Find here a clip http://www.youtube.com/watch?v=8etlpBbC6o4
I do enjoy watching Shodokan Aikido but their striking is always followed by an Aikido technique, it seems. Not to say that that's improper, but the atemi I wish to see more of consists of continuous strikes (that work alone and could win alone) until an Aikido technique presents itself. I've rarely seen randori like that, though. Nice vid!