I may well buy it outright eventually--the whole thing, not just part 2. One Piece is one thing, but the idea of buying the entire Naruto anime feels like a very imposing prospect right now. I haven't even started, and the fact that it streams legally online takes away the incentive to do so. However, I'm pretty patient, I can check out new volumes in Borders and hold out for some super all-inclusive set.
Alternatively, given how insanely popular Naruto is, Viz Big editions are inevitable. I just hope they go "Naruto Nation" on those when the time comes. It's taking them a good chunk of time just to get through the 28-volume Rurouni Kenshin.