Outlook 2007 is slow, Need Improvement?

I know most software have bugs, Microsoft is on the list for sure.
But till now, the most unacceptable software is Outlook 2007

which always hangs and slow during startup and Send/Receive


many Service Pack released still doesn't address the problem, people keep complain to me and writing blog about this issue..., finally got this : " no matter You use Windows XP or Windows Vista, Outlook 2007 still stuck"

in my case most user are still on Windows XP + Outlook 2007.
please let me know if you found a really good fix/solution other than the solution listed below:

• remove / unchecked all add-in from Trust Centre
• install kb933493 , 2007 Large PST Performance Issuehttp://support.microsoft.com/kb/933493
• tuning the "TCP Window Scaling -> disable it" , only for vista, but most of my case is still Win XP which have this disabled by defaut
• Disable Instant Messenger "Online Status" contact
• Disable RSS , but I have no feed subscribed

many suggest to reduce PST / OST filesize, does Outlook only work for Small-Medium-Enterprise user which business 're not big enough to build up the Giga-byte large PST ?