I was initially very disappointed when I discovered that with ACT! 2010 I always had to first click in the "Look For" search box before typing a search term. Then, by accident, I discovered that - after doing such a search - if I just minimize ACT! using the simultaneous depression of the Windows Key and the letter M, then the next time "bring up" ACT! using the ALT + Tab sequence, I just start typing the search term and it appears in the "Look For" search box and the contact list search is done.
For reference, if ACT! is minimized using the dash in the upper right corner of Windows, the above doesn't work and one has to click in the "Look For" box each time. Also, the previous version of ACT! that I had before ACT! 10 would do what I have described - no matter how ACT! was minimized. But, when I inquired about ACT! 10 not doing so, I was told by Support that there was no plan to re-establish that feature. Anyway, it's a happy outcome for me.