I have used Western Digital for years and i think they are not as reliable as other manufactures, i purchased a 250 G Hitachi a few months ago and so far so good, ive had 3 brand new WD hard drives choke on me in the past 2 years.
i don't know, i have own maxtor's hd and they are fine. though they do have problem with nf4 chipset. I think all hd will fail so i think all big companies are making decent quality hd. With seagate offering 5 years, I gues sthey are now the best quality and my no 1 choice of hd.
You are correct. All parts will eventually fail. Looking at the warranty is the best way to determine the MTBF that the drive makers think their drives will handle. After all, they don't want to be replacing drives all the time.
2014 is going to be a good year. More content, more streamlining. Be a part of history!