Mano Marks and Pamela Fox both twittered about a competition to create a new style of map pin over at 99designs. Here's a screen shot of one entry:
If you didn't know, that effect that makes it look like a reflective curved surface is the 'web 2.0 look', this style is common amongst the entries to the competition.
Pros: Applying this look has the effect of impressing your audience that you've produced a professional looking design (I have tried to produce it myself, getting it to look like this is no easy business) and also that you're using the latest fashionable look. In any GeoWeb context this is important: studies have shown that people are more forgiving of minor web page malfunctions when the overall look is professional.
Cons: Icons work well on normal web pages as they are plotted over plain background, the designer can make the icon complex by applying a web 2.0 look without compromising the ability of the eye to locate it and identify it. However, a map pin can appear against any background which means your visual system needs to work fairly hard to even pick the icon out against the background. Try finding the beige circles on the left of this image which I captured from a view of Scotland in Google Earth:
tough isn't it? (BTW there's 4). If a designer applies a web 2.0 look to an icon in a web map your visual system has to work hard even to resolving the map pin against the background. Its better to compromise some of the professional look and use a simple icon with a simple white/black halo as I've used on the right here.
Aside: This doesn't mean you should always use very simple shapes such as circles, meaningful icons such as a simple elephant icon to denote an elephant have lots of advantages.
Exception: If the base map is a simple street map with plain colors then applying a complex design to your icons becomes possible again.
Google Default Icons: These have a similar web 2.0 look. They're consistent with the google maps icon set which is good, but IMHO a different, visually simpler set would be better for use in Google Earth.