kerravonsen | The Importance of Having Icons

The question I've been wondering... now, I have a free account, so I only have three icons, but if I were to get a paid account -- with its fifteen, isn't it? -- what is the best use of Iconage? The most effective/efficient? What kind of things are best placed in those slots? I mean, people tend to use them as mood icons, or topic icons or just I-like-this-actor icons, but...

To take my current three icons, I use my default Avon/Cally icon most of the time. It's default, and it's basically a "this is me" icon. Then there's my Jim-and-Blair icon, which has the word "buddies" on it, which I tend to use when friendship-related stuff comes up. And then the Methos icon tends to get used (a) when Methos is mentioned (b) when historical/mythological things are mentioned (c) just when I feel like it, because it's a cool icon.

So, how do you use your icons? And how does one get the most bang-for-your-buck in icon usage? For example, since I use the Avon/Cally for a "this is me" icon, it would, perhaps, be redundant to have another "this is me" icon, because then I'd have to worry about which one to use.
On the other hand, I really like astrogirl2's "Go You!" icon because it's such an encouraging thing to see, and is used in congratulatory posts. So, what are your most useful icons?