I would always choose an external filter over an internal, internals take up so much space and are a pain to take in and out of the tank to clean.
I always use Eheim, that said, the Ecco filters are, IMHO, not the best. They were introduced as a cut price, and consequently lower quality range to compete with Fluvals and so forth. Most of my units are the older "Classic" models, but I also have some of the "Professional" range as well, (which are simply updated classics in a new box after all). These are so superior it is difficult to express.
I trialled a "Wet and Dry" model as well, not for me. Noisy and the surging output was bad for my quiet plant tanks.
If I were you, I'd go for a 2211 Classic, or if you're feeling flushed, a 2222 Professional.
To a certain extent, it depends on what you are going to keep. A heavily planted tank lightly stocked with non-messy fish will require, and indeed benefit from a smaller filter. Messy fish or fish that come naturally from higher energy environments like the current a larger filter produces.
