Too much GPU?

APPROXIMATE PURCHASE DATE: Within two weeks

BUDGET RANGE: approx. $350

USAGE FROM MOST TO LEAST IMPORTANT:  Gaming, gaming and occasionally gaming. 

CURRENT GPU AND POWER SUPPLY: 
None

OTHER RELEVANT SYSTEM SPECS: 
This is a new build:
Phenom 2 965 Black Edition
Asus Crosshair IV Formula
4gig G.Skill 1600 Ram


PREFERRED WEBSITE(S) FOR PARTS: 
Newegg.com Frozencpu.com and local shop

COUNTRY OF ORIGIN: USA

PARTS PREFERENCES: Ati

OVERCLOCKING: No.  I fail in the patience category.

SLI OR CROSSFIRE: Maybe 

MONITOR RESOLUTION:  1920x1200 

ADDITIONAL COMMENTS: I play mostly Steam based FPS's like Mass Effect 2 and on rare occasions some mmo's.   My main concern is not to gear the computer towards any specific  game but just well balanced throughout all games I will play.

I see on another thread that Crossfiring 5870's creates quite a bottleneck on the guy's 1090T, giving him only 5 - 10 FPS when running two cards.  If the gains in crossfiring are that minimal then I fail to see the finical justification.  

My question is, is crossfiring this system beneficial?  Due to the bottlenecking issue I feel that purchasing one really good card is just as good as crossfiring anything else.

If I don't crossfire, am I better off waiting for the 69xx's to be released? Even if it is just to wait for the price drops on other cards?

Or is the bottlenecking not that serious?  I apologize if I am being vague but I am at a loss.  My original plan was for a Xfx 5870 but then I found I could crossfire 6850's for roughly the same price which limits my ability to upgrade.  

Thank you greatly for your time and input.