That all looks like a good choice of hardware. I Think i'd go with 4 x 1gb of ram to be honest. Saves money.. you get tighter timings and 2gb will be better down the line but your next upgrade will probably be to DDR3 anyway.. (maybe get a mobo that supports DDR2/3)
Personally I'd get the Abit IP-35 (no ddr3 support) it's a fantastic board for everything, overclocking ( medium clocks), raid etc.. and lovely build quality.
Dont go with gigabyte.
The OCZ kit is pretty much the best value for money 2x2gb kit I can think of and should do you fine but i'd still be tempted by 4x1gb.
The slowest ram you need for the q6600 is 533mhz RAM as you said but i'd have 667mhz or if you want some serious overclocking potential.. pc6400 (800mhz)
The PSU is a good one as i'm lead to believe so should be fine for that system especially with the low power graphics card.
I'f you aren't gaming I can thoroughly recommend the Gainward 8500GT SilentFX (passive) lovely quality passive solution. Stays around 45 degrees idle and gets to about 60 in games so you shouldn't be able to push it any harder than that.
I also used the scythe ninja rev b in my silent build. It's a fantastic cooler. my E6600 was 18 degrees idle using it at stock settings and it has almost all the overclocking potential as the very best coolers (thermalright 120 extreme etc..)
Futher Advice: Build it!!
