Original is the best for me, I wish it was in game when I started playing... It is great introduction to what happened to us and was perfect combined with original Wailing Prison tutorial. Unfortunately I saw it much later on the internet, so the immersion which it could give at the beginning was long lost. It is honest, shows the game as it is and doesn't give any fake impressions.
"Tamriel Unlimited" version with same voice layout is just pretty action video with fancy graphics and special effects Gameplay in Cyrodiil is far from being this epic, I remember being fooled by this intro (in unedited, longer version) and expecting so much from Cyrodiil, how great was my disappointment when I first went there
Nothing beats the goosebumps from seeing the cinematic trailer for the very first time (which is the extended version(s) of this one - see it here) -- how the heroes from each alliance meet, are forced to work together briefly, and all the chaos that follows.
"Feet are for walking. Hands are for hitting. Or shaking. Or waving. Sometimes for clapping."
- M'aiq the Liar