hi... thanks for your words...
Usually I send the EPS file and one AI file... they are almost the same format... both vector and to use with Adobe Illustrator/Indesign.. Coreldraw or professional programs... also to use for printing providers... I send also a PSD layered file... this file is to Photoshop users... usually 5000pixels wide... very useful, specially for web uses, you can reduce the size ofcourse :) .... also a PDF file, this is useful to send to other people to know the logo because almost everybody can read without problem, the JPEG file and the PNG file, the PNG usually is a 5000pixels wide file with transparent background... perfect to use with the typical office applications (MSOffice, Openffice,...)... you can use to create your own presentations, memos, fax,... and all them for all the versions of the logo (color, grayscale, b&w, w&b)
I don't know what others designers do, but I think that with all these files the CH have a lot more of chances to use the logo without depend all time from professionals
Just let me know anything more you wanted
Bests
fermat