[quote name='Trenchalicious']4 Gigs is all one should really need tops.[/quote]
I use my PSP for things like music as well. I like having games, movies, and music all in one package. I see no reason to purchase and carry another piece of hardware that won't even have as nice of a screen. 8 gigs would be awesome as it would allow me to keep an entire season of whatever show I'm watching, along with some music, gamesaves, pictures, etc.