Let's not. Please. Personally, I find the colored smileys that so many services insert awful:

1. They break the flow of text
2. They tend to be larger than normal characters, making the line they are higher and so inserting spaces between lines.
3. Unnecessary overhead.
4. Ugly (very personal choice of course but there you go).

If we're going to add something to chat let's make it useful, something like having code blocks displayed with a different background `like this` so we could easily paste commands in chat. As it stands, we just get a fixed width font, no background and it is easy to get confused.