Memoroy for Intel 875P

There seem to be two pricelevels for 1GB DDR 400 memory from various
manufacturers:

$170 - "value" memory
$250 - made specifically for dual-channel MB's like Intel 875P


1. Do I neeed the more expensive memory?
2. If not, what do I gain by going for the more expensive?
3. Does anyone know which type the Dell Precision 360 originally ships with?

Thanks.

Alan