The time honored respone to all caps posts is...
Yuo suk at teh internet!!11!1!
kepp prakticin11!!!
And the following information....
Do not type in all caps. Typing in all caps is considered yelling or screaming online. Those who type in all caps are perceived as lazy and not being considerate of those who will have to read their e-mail. Various studies on the topic reflect that it is more difficult and takes longer to read text that is typed in all caps. And for those who question "What studies?" here is one example for your reading pleasure:
http://www.psych.utoronto.ca/~muter/pmuter1.htm
Searching for words is faster with uppercase characters, but reading of continuous text is slower (Vartabedian, 1971), perhaps because interline masking is greater with uppercase (Nes, 1986). In addition, lowercase enhances reading efficiency because word shape is helpful in word recognition (Rudnicky & Kolers, 1984).
One is free, at their convenience, to review the entire document above which goes into detail about how eyes react to what they have to read based on how the content is presented.
Stating certain professions are required to type in all caps (that's the first time I've heard that one) does not jive either. Would you send any off-line communications in all caps - the answer is probably no.
-Sean