GT5 passes Halo Reach in global lifetime sales!

[Jaywood2010]

1	Halo 3	X360	2007	Shooter	Microsoft Game Studios	7.73	2.72	0.13	1.18	11.77
2	Halo: Reach	X360	2010	Shooter	Microsoft Game Studios	6.71	1.80	0.08	0.85	9.43
3	Halo 4	X360	2012	Shooter	Microsoft Game Studios	5.63	1.80	0.04	0.76	8.23
4	Halo 3: ODST	X360	2009	Shooter	Microsoft Game Studios	4.20	1.29	0.06	0.60	6.15
5	Halo Wars	X360	2009	Strategy	Microsoft Game Studios	1.32	0.74	0.04	0.22	2.32
6	Halo: Combat Evolved Anniversary	X360	2011	Shooter	Microsoft Game Studios	1.29	0.62	0.04	0.21	2.16

1	Gran Turismo 5	PS3	2010	Racing	Sony Computer Entertainment	2.59	5.11	0.80	1.92	10.42
2	Gran Turismo 5 Prologue	PS3	2007	Racing	Sony Computer Entertainment	1.25	1.79	0.57	0.52	4.12
3	Gran Turismo (PSP)	PS3	2009	Racing	Polyphony Digital	0.43	1.40	0.31	0.67	2.82

X360 Halo - 40.05m

PS3 Gran Turismo -  17.36m

There really isn't that much of a competition.  If you are trying to start a fan war, bravo because you will achieve it.  But Halo has been a much bigger franchise all generation.