The title says it all. Wich one is it in your opinion? (i really care, i want to start an only Shout Dragonborn character)

Good luck with that. Shouts aren't like skills (although there is a mod which adds a shouting skill). So if you don't boost any of your skills, you're likely to get killed pretty swiftly.

As for the best race, I'd go with Nord, simply because the only tongues in the lore are nords.

Nord or Imperial as most will probably tell you. The entire main quest seems to be made with these two races in mind (Nord moreso than Imperial, but the fact that you're crossing the border at the start of the game leans more towards Imperial unless you're an ignorant Nord outlander).

Of course for the cosmic irony of the gods an Altmer would make a pretty good Dragonborn. Their long life-span would actually make them the best "Thu'um Masters" as they would have more time to meditate and such.

Shouts affect every race the same way so that means this thread will soon turn into a "which race is better" thread....

I'm gonna say Nords.

Also, I would do the Fortify Shouts glitch. It would make being a Thu'um Master much easier.