Budget Gaming System!

Hi folks,
I'm building a system for my parents, it will be used for internet, and basic applications like word, publisher, powerpoint. But it will also be used for some gaming, mostly Starcraft 2, medieval total war 2, and assassin's creed.

I need to keep the budget under $700, as low as possible is best, while still getting max settings in games at 1680x1050 or 1440x900 if thats needed for max settings.
Probably will not overclock for awhile if ever.
Also a friend is giving me his old 680i board so I can save money there.

Here is what I have so far:

SAMSUNG Black 22X DVD+R:
http://www.newegg.com/Product/Prod [...] 6827151171

Western Digital Caviar SE16 WD6400AAKS 640GB 7200 RPM 16MB Cache:
http://www.newegg.com/Product/Prod [...] 6822136218

OCZ Gold 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800:
http://www.newegg.com/Product/Prod [...] 6820227124

E8400:
http://www.newegg.com/Product/Prod [...] 6819115037

I have this case and the PSU in a combo that gives me an extra $20 off:

Antec three hundred:
http://www.newegg.com/Product/Prod [...] 6811129042

Antec Neo Power 500 500W:
http://www.newegg.com/Product/Prod [...] 6817103940

Microsoft Windows XP Home Edition:
http://www.newegg.com/Product/Prod [...] 6832116511

Total on all that is: $481 - $20MIR = $461

What I still need are:

Monitor:
I need to get a new monitor, I'm guessing it'll need to be 19' although 22' would be really nice. But I don't have any idea what would be a good deal and good quality.

Graphics card:
I want to go nvidia since I'll have the 680i board which can SLI, I was looking at a 9800 gt but don't know if it would give enough performance. I hear the 9800 GTX's are nice as well.

Thanks in advance!

Edit: I'll be building this closer to Christmas time, will prices be more favorable then? I also might pick up any good deals on black Friday.

The best thing to do with monitors is to visit several big box stores and compare them side by side. Some things just don't translate well in print like viewing angle, gloss, viewable size, etc. Look for deals and sales, especially on BF. You can buy one at a big box store, often cheaper then newegg and no shipping, you can also check it after you buy it for dead pixels or other problems and get an immediate replacement. Decent tutorial on LCD monitors and remember to be careful how you clean it !
http://www.hardwaresecrets.com/article/87

Also I was wonder which of these HDD's was better.

I found this seagate with a 32mb cache:

http://www.newegg.com/Product/Prod [...] 6822148335

And this is the WD I originally posted:

http://www.newegg.com/Product/Prod [...] 6822136218