Just got some info about real Wii U HDD capacity. Actuall free space on 8 Gb (which is happened to be 7.2 Gb not 8) hdd will be 3 Gb, cause 4.2 Gb are devoted to profile data storage. The same story with 32 Gb, only 25 Gb are available
So whateve version you buy, just add some external drive
P.S. and one more intresting news - 5 Gb update awaits those who bought the console at the vary first day