i have WHM/Cpanel -- stable release and mysql 5.1 is happy.. the easyapache upgrader is the way to go in WHM too
also apache 2.2.14
but there is a BIG nono... don't upgrade past php 5.2.12!
5.3 and 5.3.1 will break ubbthreads... this is because about 5 functions are deprecated and in php 6.0 will be gonzo all together..