I concur with the previous answers by Don and Joe. Although I would since I am designer. It's encouraging that non-designers understand and appreciate that value that design can add to a business.
Nothing screams generic and thoughtless these days more than those "trite cliche... multiethnic, posed stock photos..." as Don so eloquently and humorously puts it.
And since differentiation and positioning is the name of the game for any business regardless of size, these sorts of images do nothing to help you get "into the mind" of your client and separate you from the rest. Not only do you need a positioning statement but you need visual images that complement your unique message.
A great and timely article on branding startups was just posted on onstartups and can be found here.
I had a boutique client (4 people on staff including the two owners) this past year that had the same problem. They are IT consultants and provide server solutions for other small and medium-sized companies. They told me they had a "credibility" problem with their prospects because their previous marketing materials were not very good. They had really generic stuff with lots of these stock business and server images. So we did something a lot more "graphic" and original. They are now in love with their new look and promo materials, which have been both noted and favorably commented on by many of their prospects during sales calls.
So I have seen results in my own experience with firms with your profile. Two cautionary notes:
- Coming up with something unique to you and your firm is not necessarily cheap, especially if you want to work with a good designer.
- Make sure you vet the portfolio of the designer you work with. Each designer has a niche and is better at one type of design than another. "What you see is what you get" since most designers worth their salt tend to develop a style over time.
Finally, here are some sites to help you get started looking for the right designer (and these sites are loaded with talent):