New Budget Build - Input Please

[CannonDub]

I took advantage of some holiday specials and am building a new computer for myself. Currently I have:

ASUS A8N-SLI Deluxe
Athlon64x2 4400+
BFG 8800GTS 640MB OC
4GB Patriot Performance DDR PC3200
Antec SmartPower 450W
3 SATA 7200rpm HDD
22" LCD @ 1680x1050

It's been a good system and lasted me over 4 years. I have been wanting to build a new computer for quite some time but 2009 was a rough financial year for me so I had to keep pushing back my build. I really wanted to build a machine around an i7 920 but I just couldn't afford it. I came across a great combo deal on newegg for the following parts and decided it was a great upgrade for me at a very nice price:

AMD Phenom IIx4 955 BE
ASUS M4A79XTD EVO
GSkill DDR3 1600 4GB (2x2GB)

I am only buying what I need right now, and will upgrade as I am able. I will be using my 8800GTS in the new build because a new GFX card doesn't fall into the 'need' category. Same goes for the HDDs. However, I am in need of a new PSU. Mainly because my current one is low on wattage and it likes to 'chirp' from time-to-time, which means it could go any day. I plan to OC my processor and when I add a new video card, I plan to use my 8800 as a PhysX card.

My Questions:

1. Based on the parts selected and the fact that I want to OC and eventually add a new GFX card using my old one as a PhysX card, what is the minimum wattage I should be looking for in a PSU?

2. Do you have any recommendations for a budget PSU and/or a PSU&tower combo? I have been looking at this one. I could use my old case, but it has very poor airflow. I would say that the most I am willing to spend on a PSU and case combined in $150-$175. Obviously, the less expensive the better.

3.Can I expect a noticeable performance increase with these new parts even though I am using the same GFX card?

 

[troisanh]

http://www.newegg.com/Product/ComboDealDetails.aspx?ItemList=Combo.304807

Since your going to use old gpu later as physx card, if not save 20 bucks and get the 520w PS combo.

 

[Dangman]

1) At least a QUALITY 520W to 550W PSU with at least 40A on the +12V rail.
2) Troisanh listed a good case/PSU combo with a bit more headroom
3) In gaming? Most likely. In general usage like web browsing and movie watching? Probably not. In video editing/photoshop? yes.

 

[CannonDub]

My parts have arrived and I have been read the motherboard manual cover-to-cover as well as done further research on my CPU. I have a few concerns.

First of all, I was reading a Phenom II vs i5 review here and I came across this:

The combo I purchased is contained in the quote below

AMD Phenom IIx4 955 BE
ASUS M4A79XTD EVO
GSkill DDR3 1600 4GB (2x2GB)

Question:
1. As you can see, the CPU I chose supports DDR3 up to 1333MHz. However the memory included in the combo I bought is DDR3 1600MHz. Will I be able to use this memory with this CPU?

 

[Xiphos]

Question:
1. As you can see, the CPU I chose supports DDR3 up to 1333MHz. However the memory included in the combo I bought is DDR3 1600MHz. Will I be able to use this memory with this CPU?

yes it will work, people use memory as fast as DDR3 2000MHz

 

[engiNURD]

1) yup. DDR3-1600 can run at DDR3-1333 if need be. or, you can run the RAM at its rated speed by using a higher ratio (ram multiplier).