I've found that most of my clients who want Illustrator art in a Word file really want it to look good on screen and for PDFs. Whenever they import an EPS file, it looks bad on screen and prints bad. Using Illustrator CS, I open good Illustrator art and choose Save for Microsoft Office from the File menu. This creates a PNG file which can be easily imported into Word and which looks good on screen and prints out decently. If you make the illustrator art larger and then scale the PNG in Word, you will probably increase the quality, but in my tests, the art printed out very nicely at 100%.

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Dennis E. Henley
Chicago, IL

As I just found out myself, 'Save for MS Office' aka PNG is just another bitmap format. A JPEG would fulfill the same purpose.