I actually really enjoy the visual research part of the design process. Some people like to be more isolated from visuals when designing, but I like to be surrounded by them (I always have inspiration boards up in my room). When collecting my imagery, I usually open an illustrator document, and then drag in tons of images from the web. Then I will often print them out and collage them all together. Often this can provide a great overall style and color story for my design.
This is an example of a collage that I made for The Collective I ended up changing my design, but it still provided a great jumping off point.
Other than the basic google & Flickr searches, here are some other sites that are really helpful & fun to look through.
Right now I am in the process of doing visual research for two new projects. I will update the blog with my research when I am done!