Hmm... I can't remember what I voted in the poll. Although thinking about it now, I don't know what I would vote...
The media options (TV, radio, newspapers) is all tampered with to show bias on whatever side they wish and whatever their biggest investor believes.
Libraries are quite often out of date and when you think about history, there is alot of controversy as to what they hold being everything.
Wikipedia is probably the most up-to-date place for information, but it's reliablity is very much under question, a place where almost anyone can change information can't be classed as reliable, even if it is a good source of information.
Search engines tend to give you information about what you need to know, so are reliable in the fact that they are giving you a variety of hosts holding the information you seek. They will always come up with something and it's not the search engines that unreliable but the actually sources themselves.
Online forums/Blog Sites are just bloody dangerous, but to find information about an social event, although possibly tainted by opinions are generally reliable.
Word of mouth is always based on what someone has said plus their opinion and various other spins on it... so generally not very reliable unless from the horse's mouth and even then can be misread/understood.
Q&A sites are opinion/knowledge based and you have no idea who is on the other end of them. For accurate, reliable information of factual knowledge they should be taken with a pinch of salt, for subjective knowledge I'd have said they were good.
Pretty much all of the options have their own bias towards what they are telling and have their strengths in a particular field of knowledge. Everything can be counted as unreliable when you think about it, but on the same note they can be counted as reliable, depending on the information needed and your opinions on the deviancy/censorship of the source. I mean you could hardly call libraries (or any of the above really) to be the best source of information in China for example, especially to find information about the country or information about anything that go against it's government's beliefs.