2nd self made pc project, the smaller the better, but still enough capacity

new confiuration minipc, before i was thinking about buying an Acer Aspire L5100 with optimal dimensions 6x20x25cm,but that would be too easy, i need some headache by making a selfmade pc:
Cause of the small size, everything has to fit and temperature issues must be calculated.
The mission starts, making the shopping list, not easy to bring all the different specifications together... min. 800MHZ FSB, DDR2, max. 65W, mini-ITX, SATA2, 7200rpm, 2,5" mGPU / IGP

There are mini-itx with intel atom onboard, also much cheaper solution, but they are too weak in my opinion, also there are acer aspire revo , asus ee box nettops

Samsung SN-S083A, SATA, Slim 
2,5" SEAGATE Momentus 7200.3 320GB SATA II 
JOU JYE Mini ITX NU-528I-B-CR 250W SFX
INTEL Pentium Dual-Core E5200 2x 2.50GHz     /maybe Pentium Dual-Core E6300 2x2,8GHZ both 65Watt TDP
Zotac 9300-ITX WiFi, GeForce 9300, Mini-ITX (dual PC2-6400U
CORSAIR    4GB CL5 TWIN2X4096-6400C5                   
alltogether about Euro 380,-
will be continued...