I was wondering, besides for games like Far Cry, is 1Gb of RAM really worth it? And if I get 512mb, should I go for 2 x 256mb sticks or 1 x 512mb sticks so I can upgrade later on?
Well, do you mainly play games with the PC? While there's so much more to computing than *gasp* games...I'd still run a Gig. Why not? Someday you may decide to take up memory intensive hobbies and you'll be set.
On a side note...I'd really suggest looking at memory specs and learning about them while you can. It's, well, pretty exciting to learn all this neat stuff. Last night I sat up reading Abit and OCZ forums until 4am, and I still feel I need to go back in there to get a better grasp.
Something I learned from doing so: Due to Athlon64's onboard controller and the many/frequent revisions they do to it, it's too hard to recommend a specific type of RAM for them. One guy could do great with a PC3500, while another may not see benifits until with PC4000.
I also saw the point why I need to stop recommending fast ram on AMD's like I use on a P4 build. The Intel's are speed dependant and do well on items like PC4200-PC4800, while AMD's should really look for PC3500-3700 Enhanced Bandwidth RAM...and that makes perfect sense to me. I have no idea why I never concidered those aspects!
And then there's the side of what's usable and what's not. Like getting PC4800 memory would only be worth while on a P4 2.4C as these are the only CPU to use a 300FSB repeatidly. Any other CPU wouldn't fair as well and may be better off with something like PC4600.
Anyway, see what I'm getting at? There's a lot to learn and understand! Capacity would be the most MINOR thing I looked at. Then you get into timmings...