I really dislike motorbikes, especially when you are walking along right next to the road and one passes by. The noise literally makes me shudder inside and causes my awareness to "freeze" for a few seconds. I can recover pretty quick after they have driven past, but if I was exposed to a revving noise, I probably would not be able to compose myself too well.
The other main thing is loud music, as in concert level loud, or what teenagers (like my dad

and sister who will both be deaf in the next few years I'm sure

!) Like the volume to be on their iPods. I can remember one time on holiday when eating out, we went to a restaurant that had a group playing. For whatever reason, as time went on, their music got louder. Eventually, I was too distraught to sit their comfortably and begged that we go, but my family did not pay too much attention as I was not in the best of moods at the time. Another problem area is the car, when the music is too loud, mum usually has to remind above mentioned family members to turn it down as I cannot really function in such a noisy enclosed environment.
In general, I don't think my sensory issues are as bad as some others here. I also dislike certain sensations such as nail files (SHUDDER) and certain pressures of touch. The main smells that cause me problems are fresh paint and nail varnish. They just make me feel groggy.