1st build, hardware advice

[LittleBear]

My laptop has died, and as a result I thought I'd take this opportunity to learn how to build myself a pc, and get the most out of my money.

My budget is not big, being the poor student I am, at around £300 - £400 (about US$500 - US$650). With this I want to get the best performance I can. It will be used for work, browsing etc, as well as HD video editing (hopefully) and some gaming (nothing big, just like empire:total war etc). I am not in need of any peripherals or an OS, as I have a separate budget set aside for that.
The build(s) I've come up with are -

MOBO - Asus P5Q / Gigabyte GA-MA770T-UD3P
GFX - ATI RADEON HD 4850
CPU - Pentium Dual Core E6300 / AMD Athlon II X2 250
Case - Antec 300
PSU - OCZ 400W StealthXStream PSU
Memory - Crucial 4GB (2X2GB) DDR2
Storage - Seagate ST3500418AS 500GB
Optical - LG GH22NS50 22x DVD-RW

I'm really not tied to any of these components so feel free to mix and match, and I'm not brand loyal, so I'd be happy to hear what people thoughts on Intel vs AMD are etc.

Any help would be much appreciated. Thanks.

 

[objecterror]

Unless you are running a 64bit OS you could probably do the same amount of editing, gaming and browsing on 3GB of ram.

 

[LittleBear]

I was planning on using windows 7 in 64bit. With DDR2 memory being so cheap it seems pointless to not get 4GB, especially since to run HD video editing in Vegas pro it recommends 4GB.

Any other advice? I'm especially interested in idea's on different Mobo's, and was wondering peoples thoughts on what brand of HD 4850 i should look at (i.e. sapphire, HIS, XFX, ASUS etc).

Thanks.