Andrew S

Pretty much what has been said before:

* ukemi - you need this to survive any kind of practice, plus it is the one "technique" you WILL use in real life.

* basic movement (irimi, tenkan, kaiten) - this is the core of the most common techniques, and can easily be "spiced up" with the introduction of taisabaki to avoid being clubbed with a bokuto or spitted with a jo.
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* seiza (and by extension, shikko and reiho) - Asai Sensei said that suwariwaza were good for keeping people humble. Great for developing hip movement and posture.

My ￥2 worth (and at the current exchange rate, that's not a bad deal!)