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.

Haven't played Tropico 3, but Tropico 4 and 5. You should be aware that Tropico is something completely different from Anno. From a strategy game players point of view Anno is much better because the game works in an understandable way, wheras in Tropico it's hard to understand why this works or not. Tropico, although being a great game, is more about having fun than being challenging and building an efficient system.

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.