ELUMEN - a product made by goldwell is amazing!
your hair feels better than natural hair once it's on, and the color stays brilliant for a long time
http://www.elumen-haircolor.com/
i cannot say enough about how much i love this product
i have had brilliant reds/oranges.... i've had a rainbow gradient... i can post photos later if you like
* to answer the original question - i think different hair colors can be really beautiful and amazing if they are done properly (ie, with elumen and a stylist).. it can look really fashionable/sophisticated and still really stand out. it doesn't have to look "immature"
and it doesn't have to wreck your hair!