Just lately we have been using www.istockphoto.com as a really good resource for sourcing images for clients. Some people begrudge paying for a photo, but some of the sites we are currently working on really come alive with good imagery.
For web you do not need high resolution images, so iStockphoto can be a affordable resource, 1 credit per image is a good price.
We find that images with people in always seem to work well, it must be because as humans we are curious creatures and relate to faces and people more so than objects. This is why big advertising campaigns always use a face. Even for your brochure web site, a face popping up here and there is not such a bad thing, engaging your visitors is always recommended.
Why not have a look at iStockphoto and see if there are any ‘killer’ images that reflect your business and what you are trying to portray?