I'd go for 4 now, I also went directly from 2 to 4, it was a real worthwile step! I'd assume Curious Labs is going to give at least the customers who bought 4 or ProPack from them a better upgrade price. Normally software houses have a date after which you buy the previous version you get a FREE upgrade to th ecurrent one (they do that to keep sales from drying up after the new one is announced but not quite ready) but we probably aren't close enough for that, yet.