I don't put stickers on my car much either.
I have two
on the car, well on windows anyway: The noticeable one is just a thin box with letters that says "Zombie Outbreak Response Vehicle" and it is in the middle of the very top of the hatch window, just under my third brake light. It's not super gaudy, and I get so many people stopped behind me at lights taking pictures of it with their cell phones.

I'm pretty surprised it's held up perfectly though, because it gets sprayed with washer fluid, and scraped by the beam blade wiper, a ton. The other one is black (on the tinted side window) and says "
GolfmkV.net" which is my bf's DIY site.
I have a crap ton of other stickers from the parts/racing companies that I get my upgraded VW parts from-- most of them end up on the press, or the work bench. I'm not like some of the ricer lame-os out here that have to cover their cars in parts brand stickers to show off how "modded" their car is though (for most- I think they just buy the stickers and don't actually have any of the parts, or if they do it's something stupid that doesn't really effect performance anyway). Plus, the stuff that goes into my car is generally pretty impressive- from companies that cater only to german vehicles (and Saab)-- none of the honda or subaru guys would know what they are anyway.
I make a point to keep my wagon at it's current "sleeper status," because I don't need stickers to show off how big my car's nuts are, and because it would look overdone and stupid-- I like to keep it clean and sleek-- at least as sleek as a station wagon can look

(what "sleeper status" means for those who don't know, is this car looks like a soccer mom mobile-- but it's really horrifically fast)
As for the scooter, I actually took the new stripes off a couple days ago. They looked too goofy and cluttered for my taste. I took the "Serenity" decal that I made off too. I don't think I'm going to put anything back on there any time soon. With the side panels painted it looks better without anything on the front cover.
The firefly sticker is going-- I'll try again for another one, but it's in a fairly unnoticeable spot anyway.
I'm going to focus more on some snazzy mods as opposed to stickers and stripes. Like a new side mount LED license plate bracket... I finally get to lose that annoying mudflap thing!
EDIT: I do have a bunch of stickers from different gun and gun parts companies-- those are for my gun case, because it's a really ugly gun case

I WAS thinking however of putting the "CAUTION STAY 100 METERS BACK OR YOU WILL BE SHOT" one on the back part of the rear rack-- but I think it might get me in trouble, especially if I am ever pulled over
