Visit_Thailand - 9:13 am on Apr 14, 2011 (gmt 0)
I have two Win7 Ultimate 64 bit laptops and one needed I think 15 patches and the other 23 or so. Both have very similar things installed on them if not identical.
An XP laptop took even longer, but she is quite old now bless her heart.
Needless to say I system restored, manually backed up AND did a system image for each before updating (except for the XP)!