It should possibly be noted that for modern browsers, such as FireFox or Internet Explorer (the newest versions ONLY), .png also has some transparency. It's actually a higher quality of transparent, but not many older browsers support it. Generally, it's best to use .gif for transparency.
Other than that, .jpg (or .jpeg--same thing) is the smallest file size, while .bmp tends to be the biggest. The others vary based on number of colors, and variations thereof.
EDIT: as an aside, if you ever get a better scan of that image, fox, I can always re-modify and upload it. I seem to recall you saying part of it got cut off, or something...
EDIT OF EDIT: my aside is the first on-topic thing in this thread in awhile. Go figure.