I found that the phone only has about 14.8MB (on average) of ram to run applications after boot-up. My WSODs usually occur whan doing alot of browsing or browsing and doing something memory intensive like listening to a podcast, I think there may be a memory leak associated with browsing. I use Best TaskManager to monitor my RAM. If I have no applications running and RAM is < 14MB, I reboot the phone by turning it off and then back on. I usually don't have more than one WSOD every 10 days or more. I also am running a 2GB Kingston card which doesn't seem to be effecting ther WSODs. Hope this helps, I do still really like the phone, but I am kinda a Nokia fan boy though.
I also read on Tommi's S60 blog that by unbranding the phone you do so at your own risk and void and Manufacturer's warranty..not sure if that is true, I would like to rebrand my E62 but am afraid of voiding the warranty. For those who have unbranded e62's, what amount of operating RAM do you have just after rebooting the phone I thought I heard somebody say it was 10MB higher than with Cingular's RAM. In this case just under 25MB which would be awesome.