albatron K8X800 Pro-II and memory

ok . . . here's my second newb question.

in the near furture, once i receive my comp, i think i may upgrade the memory. my only hiccup is that it is coming with 1 gig (512 MB x2) in it. which means it is taking up 2 up of my 3 spaces for memory. so to get the most memory out of my computer i would have to buy 3 one gig memory sticks. now will 1 gig sticks fit in my memory slots on my motherboard? and if they do will it really be worth it to have that much memory over just 1 gig?