Game Setting - Opinions/advice wanted! - thank you

I'll post my specs first -
Q6600 overclocked to 3.0
4gig dr2 800
p5n-d mobo
msi 8800gt gpu (considering SLI - not sure if its worth it)
just upgraded to VISTA 64 Ultimate(yes, its very stable and I'm completely happy with it's operating and performance)
Also, considering upgrading to 8GB- yes/no?
I have a few questions with game settings/launch options

Launch options :  -heasize 1024000   too much? not enough?
In Game:  mem_heapsize 512  too much? not enough?

Also, being that I have directx 10, I set launch options to -dxlevel 100 (to get 10)
now, hardware says 10, but software says 9, am I getting performance out of this?

I tried launch option -64bit, but I cant get into gameplay.. is this supported?


FPS Averages -

Full Server/In Action - avg - 40/60 fps
Full Server/Non Action - avg - 80 fps
Empty Server - avg - 130 fps

Feedback is much appreciated!

64 bit mode is automatically set... at least in 64-bit XP Pro (Ya, don't use 64bit XP.  I've actually heard you're better off with 64bit Vista).

SLI is a personal choice... If you have a multi-screen setup, I would NOT get SLI personally.  Also, many games don't support SLI.

Since I'm use XP, 4 gigs of ram is MORE then enought.  I've never seen it go over 80% usage (even in crysis).  For vista, it might be worth it.  You should be able to get 4gigs of DDR2 800 for under 100 bucks.  If you see ram usage on the high, then get more ram.

OrangeBox doesn't have DX10 suport.  OrangeBox has LIMITED multi-proccessor suport (It does partical effects on a second core... big deal).

I don't think I messed with heap options personally.