I have my local time (Mountain) & plus Phoenix (because I never know what time it is there). Lastly, aviation guys need Zulu time, so I have London as well.
I use SMS less than anything else. There are only about 2 people that I would send a text message to and those are usually for quick coordinating for movies and things, not actual conversations.
Stocks... I guess since I'm 19 years old I haven't really thought about investing yet...
Youtube also. I don't have much access to Wi-Fi yet and watching the videos over EDGE is just a pain in the ass but luckily when school starts again this fall I will probably use it a lot more thanks to a Wi-Fi network that covers the entire campus!