I'd go for your first choice.
This is what I'm building right now. Parts sourced via pcpartpicker.com.
G3220 3.0Ghz Dual Core CPU, Asus H81M-E Micro ATX LGA 1150 motherboard, 8GB Kingston DDR3-1333 memory, WD Blue 500GB 2.5" 5400RPM Internal HDD, Silverstone ML03B HTPC case, Antec 350W PSU, Internal case fan, Low Profile ATI HD7750 1GB GPU, 2 x IDE to SATA Cards (for an Optical IDE DVD & 1 x IDE HDD), 1 x Low Profile PCI-E Wireless card.
The requirement was for a case that would be no higher than 105mm (low-profile form factor) to fit under the seat of my racing simulator. Build price including shipping came in under $A550-00.
It replaces a P4, 4GB Ram, Geforce GT9600 512MB, Dell Gx280 case, the existing DVD, 1 x IDE HDD & 1 x SATA HDD will go into the new case as well as the new 2.5" WD HDD.
The Dell is no longer upgradeable as sourcing a better PCI GPU than the GT9600 card is impossible. It lags on some graphics heavy sims anyway so out it goes.
[
www.mediafire.com] Some say you should click it, you know you want to.
[
www.gp4central.com] <----GP4 Central