Hang on there man.
Also a possible motherboard option:
http://www.landmarkpc.co.za/store/zotac-h55itx-wifi-intel-chipset-mitx-p-4511.html
RAM:
You wouldn't be able to run @ 1600mhz wihout overclocking but since for a cheap option I'd take:
Personally I'd get this from Esquire: Kingston HYPERX 4GB 1600MHZ DDR3 KIT/2 (R796.86 incl.)
Otherwise get a cheaper 1333mhz kit from wherever.
In terms of hard-drives, I've owned:
WD Green Power
Seagate LP
Samsung EcoGreen
IMHO the WD Green Power is the coolest running drive and I would recommend you get that instead but you can go for whatever. Also for the price you are paying Prophecy you can probably get a Samsung drive from Esquire, 1.5TB for R603.06 incl. or 2TB for R910.86.
Both EcoGreen drives.
I don't have an opinion on the CPU cooler, generally I only buy Thermalright and I believe them to be the best but for the case you are using it won't fit (probably won't fit the motherboard either).
CPU:
The Intel Core i3-540 is R1024.86 (incl.) from Esquire.
If you don't have an Esquire account PM me.
Also, the PicoPSU you picked is more expensive than their older 200w model, from that same supplier, maybe consider that? (Check the post I made with the PSU I recommended).
I think all of them (PicoPSUs) still run the older ATX pinouts so you need a converter to get it complaint. By that I mean the older ATX pins had less plugs, the newer one has a few extra Vouts, but you get plugs that take the current plug and expand it by going parallel on some of the wires. Shouldn't be an issue for a low power setup.
EDIT:
Ok just noticed, you mention Micro ATX instead of Mini-ITX, in that case Esquire also have 3 Asus motherboard options:
P7H55-M LX
P7H55-M
P7H55-M/USB3
Go look on the Asus web-site, they are fairly cheap from Esquire. I'm assuming you are on a budget, hence the recommendation to buy from Esquire.
Maybe someone can recommend a CPU cooler, I'd only recommend Thermalright and I think they are a bit outside of your budget and requirements (in terms of space and required cooling, IE> it would be overkill).