I am very very bad at games and need an easy learning curve. Would I be able to get into any of the games in this series (1400 looked like my favorite from the description) or would I be turned of by the initial difficulty?

If you play the freeplay-mode, you have many options to choose from, so that you can make the game pretty easy. For that you should select easy NPC-players (or none), no pirates, no desasters, many resources...

Your only concern will then be to produce enough goods, so you will get a feeling for how the game works without having to deal with fast expanding enemies, war, or your whole city being on fire.

By the way, for beginners I would recommend 1701 over 1404, due to less complexity with the orinet. But that's up to you, they are both great games.

Free play sounds interesting. See for me, I like when I start a new game like this to have an easy time of it first, then gradually ramp up the difficulty as I get better. I don't like having to learn by losing over and over and over.

As einmuzi said, Anno 1404 can be as casual as you want it; there is a great amount of customization available in free-play mode, which is the meat and potatoes of the whole game alongside the various scenarios. The campaign, although not mandatory, serves as a good & quite big tutorial but overall the game is pretty easy to learn even without the tutorial.

Thanks y'all think I might pick it up while it's on sale, trying to decide on either this or Tropico 3.

Can't help you with that; even though Tropico 3 has received generally favorable reviews, i could never get into it myself mostly due to the omnipresent political aspect, which is something i didn't like at all.

Why not both?! :P
I gotta agree with ya. Have a ton of hours on Anno 1701 and Tropico 4, my favorites, and they're completely opposite gems imho. Nonetheless they're amazing to even gaze upon, hence details, units and such.