Koffie -
To be fair though, comparing opening weeks, Madden 2008 and 2007 launched with 750,000 and 850,000 units respectively. Isn't Halo3 quite a bit bigger than those 2? Most every sales report I've seen for Madden sales vs. Halo3 preorders has put Halo 3 at a 3:1 upto a 5:1 advantage against M08 sales.
Halo2 sold to 20% of the userbase the first day on the Xbox (11.5m owners). The X360, atleast according to VGC will have over 7m users at that time. I would greatly assume that Halo3 will sell to a bigger % than that, at that time.
Not only that, but if you look at Gears of War last year, it sold 606,000 copies, which was 17.9% of the entire X360 userbase at that time.
If the X360 was at 7,250,000 units by then, even if it did GOW numbers, it'd be at 1,297,000 units. However, I tend to think Halo 3 *might* (emphasis on sarcasm) be more hyped than Gears was.
Next game you could compare, in terms of percentage, would be Madden 2007. It sold to 23.9% of the userbase (625k to 2,613k users). Using those numbers, H3 would sell to 1,732,000 people.
IMO, it should sell between M07's 23.9% of the install base, upto 35 or even 40%. It really depends on the whole "everyone that wants Halo3 already has a X360". If that were true, Halo3 could sell 6.5m copies first week :-p
Back from the dead, I'm afraid.
