I only caution you against that because the 3x2gb kits are designed for LGA1366 systems. You will not get dual-channel memory operation using three DIMMs. You might want to look into getting a 2x2gb kit and then a matching 2x1gb kit to hit 6 gb and keep in budget.
Depends on how much bling/cruft you let Win7 run in the background. I strip it down for daily use (windows classic theme, all visual enhancements deactivated . . . basically it looks and feels like Win95) and I can't really tell the difference in its RAM usage vs. WinXP SP3 with all its widgets deactivated.
If you need a 2 gb RAMdisk then I'd go with 6-8 gb, but that's just me. I do just fine with 4gb RAM and no 2gb RAMdisk.
Here's just one hint of what the Arrow offers:
http://www.overclock.net/air-cooling/650726-new-cogage-arrow-better-than-nh.html
Most people in the know think the nh-d14 is better, but the Arrow is close, and it has a lower base cost. You'll want to replace the included fan.
The BARAM . . . well here's a good post about it:
http://www.xtremesystems.org/forums/showthread.php?t=215385
It's roughly comparable to the Ultra 120 extreme without the base flatness/finish issues and at a lower price. The BARAM also fared very well on Frostytech's AMD reference platform, and still holds the #5 spot on their Top 10 list for AMD systems:
http://www.frostytech.com/top5heatsinks.cfm
For the money, it's a pretty good buy, especially if you're looking to pick your own fans for your HSF anyway.