I still would suggest going with Mushkin. They have a reputation amongst computer geeks of having the "best timing." (Whatever that means.) Do a Google for "memory reviews" and maybe "memory reviews Mushkin", and you'll get several hits.
Here's an example of what the pros think:
http://www.legitreviews.com/article/294/
I'm not an engineer, but according to what I've read, there IS a difference in RAM. There is a reason one brand costs more than others. As with anything, you get what you pay for.
Here are some quotes I found from computer hardware review sites:
"Overall the Mushkin XP-5300 2GB kit is a spectacular achievement, capable of both extremely tight timings and excellent overclockability as well. It has been a long time since truly low-latency DDR-2 was available, but with this product Mushkin has managed the impossible both 3-3-3 timings and a top speed of well over 800MHz. Despite a relatively high selling price, for Intel users there simply isnt better memory to choose right now. Very highly recommended."- bytesizedreviews.com
"What separates the Mushkin XP2 PC2-5300 DDR memory from a lot of others at this point in time is how these modules thrive on voltage. This memory offers flexibility, whether used for video rendering, gaming or overclocking. Mushkin warrants this product to run at a voltage range from 2.1 to 2.3 volts...For gamers who seek fast timings and high bandwdith at stock memory ratios, the Mushkin XP2-5300 is a very good choice. The same can be said for overclockers looking for the highest DDR2 clock speeds that they can find. There are a few memories that can go higher in speed than Mushkin DDR2, but there are very few current DDR2 modules that can do 3-3-3 timings to DDR2-700 and above, or DDR2 memories that can handle higher voltage as well as this Mushkin. For now, the Mushkin XP2-5300 is a good choice among DDR2 1GB modules in 2GB kits."- anandtech.com
Tons more... but read on your own, and you'll find what the pros think.
By the way, Mushkin guarantees the RAM you buy from them will work. "We carefully select components and program each module to match the manufacturer installed memory and provide guaranteed compatibility...Trust Mushkin's exclusive PerfectMatchTM technology. It's guaranteed to provide true compatibility with your branded...system." -Mushkin.com
Good luck.
So do you work for this guys???