I also bought mine through ADC...
I still only got 512mb of ram... main reason is because I don't have any clue what kind of ram apple uses... I didn't want to pay that much money for ram with a CAS of 3-3-3 or something that I could do better with Crucial ram. Crucial and Viking is cheap enough that I'll take the 512 and pay the same for another 1 gig to get 1.5gigs; same price as 1 gig I get 1.5gigs.... and ram I know is top of the line.
I've been building systems for a few years and haven't ever had a problem with Crucial memory. I have also always added my own ram to my mac and never once had a problem. I did have a friend who put a pc133 in a pc66 slot and fried the slot. But thats his fault
. Its hard to go wrong with DDR PC3200 Non-ECC ram
Plus side to you is you'll have 6 slots and I'll have 4 left.
But when I'm ready to throw out the 'free' 2x512 apple gave me... i'll just throw it in a PC.