When it comes to memory, pretty much no matter what speed/brand you use for the chipset that supports "that" type of memory it will work. The 955X chipsets supports upto DDR2 667 according to Intel's rules and specs but I'm using DDR2 1000 modules w/o a single issue.
In the case of the 915P and 925XE, any DDR2 module will work as well, I've tried and several people have tried different brands/speeds, except with the 915P and 925XE it only supports upto DDR2 533 which is not bad but you could always put DDR2 667 and 800s.
DDR2 is by far the best memory I've ever tried since the RAMBUS days. I haven't had an issue so far with any of the DDR2 modules I've tried and I'm very temptive to switch to a 2GB kit......but it'd be hard to get let go of these 8000ULs.