I would definitely call myself eccentric. I dress very conservatively, and also very casually. The conservative part because I have no real concept of fashion, and the casual part because "business" clothes are exceedingly uncomfortable.
The eccentric part comes in because of a photographic memory. I simply notice things most others miss. One of my last jobs with my company was as a mortgage loan processor. I would flip through the screens on the system showing the application info at the rate of 4 or 5 a second, and then stop and go back to the first screen to fix an error. Nobody could understand why I was working this way, but the reason was that it took my brain time to review what was on the first page and realize that something was wrong. If nothing was wrong, I would have just kept going, piling up mind-images of what was on the screen. Some of my bosses would assume that I was taking shortcuts and not checking certain things, so I was constantly being audited, but I never had a single error.
Now I have a job that basically entails me being a "guru" and training others, fixing issues, and showing how our products fit the market in an economic sense. I love my job. But, it means I give a lot of business meetings in jeans and a T-shirt (this is at a bank). I work behind the scenes, so it is ok, but definitely a quirk.
The fact that I have enough knowledge to fill a Time-Life encyclopedia on Colorado Railroad history is another quirk that fits in to the eccentricity part.
Then there is the fact that I put ON sunglasses walking into buildings. Last week, I was helping somebody fix an application, and they mentioned that they were sorry to bother me when I was headed out the door. I* was confused, as I still had about 4 hours to go in the office at this point, then I realized that they thought that because I had sunglasses on. I don't wear them all the time indoors (unless "indoors" means Wal-Mart) but when I start getting bothered they go on (and work great!).
At work, I tend to rock back and forth while sitting, or if I am standing up, I pace back and forth outside my office. I have a phone cord that is about 25' long, so I put a headset on and walk around (pacing) staring off into space with my head cocked playing with a slinky. I mentioned in another thread that this quirk has been recognized, so that I have a collection of slinkys given to me by co-workers. I love work, as it seems even when I am at my wierdest, people accept it and allow me to do my thing.
So yes, I am eccentric, and I love it. The problem is finding people that aren't put off by a person that doesn't quite fit in...