Hopefully this will help someone. My speeds were terrible with the settings from the Straight Talk website.
When searching I found many other APN settings in different forums but this is the only one that worked for me.
Name - Straight Talk
APN - att.mvno
Server - cingulargprs.com
MMSC - http://mmsc.cingular.com
MMS proxy - 22.214.171.124
MMS Port - 80
MCC - 310
MNC - 410
APN type - default,supl,mms,hipri
I left everything else blank. (Not Set)
I don't know what any of this stuff means I just know it worked for me.