Case+mobo upgrade

[AlexTrickle]

I'm getting quite into overclocking at the moment but my current sugo (SFF) case is letting the side down with its bad cooling and over crampedness. So I'm going to switch back to a standard ATX case with a new motherboard. I have the following two rigs:

E8600 (stock cooler)
4GB (2x 2Gb) GeIL Black Dragon PC6400
Asus P5E-VM (G35 chipset)
BFG GTX260 OC
Corsair HX620
Silverstone SG01-F
Hitachi Desktar 320GB (WinXP Pro x64 installed)
(build in august 08)

--

E6850 (Artic Cooler Freezer 7 Pro)
4GB (4x 1Gb) Corsair Dominator PC6400
Asus P5K-E (P35 chipset)
XFX GeForce 8800Ultra
Coolermaster Xtreme Gamer PSU (not sure what wattage)
NZXT Lexa Blackline
WD Raptor 74GB (WinXP Home installed)
Seagate Barracuda 160GB
(built in august 07)


I have a budget of ~£200 and need to come out with two working machines (one for parents at home and one for me at university). My plan was:

Give parents the following:

E6850 (with stock cooler)
Asus P5E-VM
XFX GeForce 8800Ultra
Coolermaster PSU (although may have to compromise as not modular)
Silverstone SG01-F
Hitachi Deskstar 320GB
Either set of RAM

For me:

E8600
BFG GTX260OC
Corsair HX620W (although as above may compromise)
74GB Raptor
160GB Seagate Barracuda
Either set of RAM
New mobo
New case


So my purchase idea was:

Antec 300 Case
Asus P5Q Pro (P45) mobo
2/3x 120mm fans


My questions are:

1) In pure overclocking terms does the P5Q Pro provide any advantage over the simple P5Q (which features and ports wise is fine for me)?

2) Best/quietest 120mm fans for the case? (Been recommended Scythe)

3) Which of the two sets of RAM will be better for overclocking?

4)If i put the Hitachi in my new rig would windows cause an issue due to the new motherboard?