It's really down to you what you want to learn to play ultimately. For starting off, and doing basic stuff like open chords, strumming out rhythm, then acoustic is definitely a winner. If you want to branch out into fingerstyle stuff, then stick with acoustic.
Electric is great for when you are comfortable with the basics, and want to break into lead playing. It's the obvious choice for rock & metal, & working with a pick. the strings are closer, so open chords may not be fretted as cleanly, but if you're moving on to barre chord/powerchord stuff, the electric can be more forgiving, where an acoustic will be very tough and unforgiving.
Personlly, I favour starting with an acoustic. It sets the right discipline, and the transition from acoustic to electric is easier. Starting on electric may encourage lazy habits early, and doing the same thing on an acoustic from coming over from electric might feel more like a step backwards.
Ultimately, aim to use the two in due course. A good, well-rounded musician will never dismiss any style, or any type of instrument to express themselves. If a song calls for an acoustic, play an acoustic. If it requires an electric, play electric. If it requires a balinese nose flute & bagpipes, then leave your guitars in their cases and play those instead!