Laurie-
A couple of comments:
Your logo is very clean and straightforward, so you achieved what you set out to do. Of all the elements, I think the envelope is actually working the best. Biz card front and back could be stronger is the logo wasn't just repeated; you might try enlarging in on card back (I mean REALLY large - it could even bleed a little on left and/or right!) so that it doesn't seem repetitious, but instead gives us another take on the logo.
the letterhead is strong, but I'm confused by the repeat of the logo in the lower right... it doesn't tell us anything new, and the best part of the logo - the line above "design," has now moved UNDER the logo.
You type choice is terrific! Very contemporary and clean!

--Chuck