Building a new gaming rig, need advice.

[Vela]

Hello.

I have a new gaming rig all planned out but I have a couple questions.

1. The PSU, will that be good enough for this system?
2. Can anyone suggest a good 19" LCD moniter for gaming?
3. I'm pretty sure this rig will be ready enough to switch to windows vista but am worried I'm missing somthing.
4. Everything seems to fit together, but could I be wrong somwhere?
5. Will the memory I chose be enough to run realy high end games with maxed settings or should I get anouther 1gb for 2gb total?
6. I was going to buy from www.ncix.com as they seem like a pretty good canadian online retailer, are they a good choice or is there a better option?
Thanks in advance.

My setup

Case:
Antec P180 ATX Advanced Mid Tower Aluminum Case

Processor:
AMD Athlon 64 X2 4200+ EE Dual Core Processor AM2 Windsor 2.2GHZ

Operating System:
Microsoft Windows XP Professional Edition OEM W/ Vista Upgrade Coupon

CPU Heat Sink:
Zalman CNPS9500

Motherboard:
ASUS M2N-E ATX AM2 Nforce 570 Ultra

Memory:
Corsair XMS2 TWIN2X1024-6400C4 1GB 2X512MB PC6400 DDR2-800 CL 4-4-4-12 240PIN Dual Channel Memory

Case Fans:
2x Antec TriCool 120MM Case Fan 3-SPEED

Hard Drive:
Seagate Barracuda 7200.10 320GB SATA2 3GB/S 7200RPM 16MB

Video Card:
ATI Radeon X1950 XTX

Power Supply:
Antec Neo HE550 High Efficiency 550W ATX12V V2.2 Active PFC Power Supply

Sound Card:
Creative Sound Blaster Audigy 4 (OEM)

DVD Writer:
Samsung SH-S182 DVD+RW 18X8X16 DVD-RW 18X6X16

DVD-ROM:
LG 16X DVD-ROM 48X CD-ROM

[flanzig1]

Ram: get a dual 1gig set for 2 gigs.
Sound card: on-board is probably as good as the Audigy 4/look to an X-Fi if needing killer sound
DVD burner: Go with a Lite-On
OS: for general gaming and use/go with XP Home