In being a beginner I believe you should go for one that would deliver the closest action and sound of a grand. With that being said I would suggest you look at the Yamaha CP5. I know from experience that this is one that deserves looking at. A bit pricey but well worth it.
I play a CP5 on stage along with a few synths and really love the action and sounds.
I've played some Rolands but to be honest I can't remember which models but I know and swear by my CP5.
In my humble opinion a beginner only a few weeks in probably doesn't need a professional stage piano designed for rugged touring use by a band. Roland, Kawai, and Yamaha all make excellent instruments for half what a CP5 runs. (Well USED to run... the CP5 is discontinued.)
Even so, on the one hand I agree with you, that the better the instrument you get the better, the more you can do with it, and the farther it will go.
But on the other hand a less expensive instrument now, and a more expensive unit down the road; when and if you have the need and ability to make use of it; is probably wiser. And this is technology after all... a brand new entry level unit has features that were only available further upmarket 2 years ago.
To the original poster: you're buying a digital piano, not an heirloom. It WILL be obsolete in a year or two; even if it lasts (25 like your Casio); but its electronic so it might fail long before then; and at that point you can either repair it or buy something further upmarket (or even just "new").
My advice would be to buy something reasonable, with good sound and good key action. Yamaha and Roland and Kawai all make very good beginner units for $1500 or less. It will almost surely last you several years; and if you run into its limits -- congrats. As long as you get some exposure to other pianos (at lessons; school; whatever) etc; you'll know when you've outgrown your instrument and could do more with something better. I'd only worry about moving up-market then.
Also, your two proposed units: FP80 and ES7 are both portable stage pianos... is portability a priority? You tend to give up some sound quality in terms of the built in speakers etc and pay more for touring ruggedness; and then you need a stand for it, etc too. If your just looking for a piano at home then I'd suggest not getting a stage piano.
Roland FP 80 or Kawai ES7?