I've said it before, and I'll say it again. If you can't find more than one use for a part, you're not Legoing properly. This excludes POOP figures (like good ol' BURPman).
If you think that specialized parts can't be used as anything else, then take a look through this guy's photostream.
I personally enjoy finding alternate uses for specialized parts, and challenge myself every time I get a new one in a set. It really helps stimulate my builder's brain. I recently used a ray gun piece for a robotic claw, made a flagpole out of a steering wheel, rod, flag and microphone, and I frequently use revolvers as angled joints. I just acquired two of those giant plastic olive green wheels from a Chima set, so I'll see what I can do with them.
The only way these parts limit creativity is through lack of effort. It takes a lot more creativity to make a coat rack out of guns that to pile up some 1x1 bricks and say it's a coat rack.