Looking at the reviews, I think I might go for the first one......
Yes, Antec is a very good brand... you still want me to look for 450 watt power supplies? I believe the video card can be easily satasfied by its amperage requirement but it does kind of seem too short of headroom/extra wattage. Is this computer overclocked?
Edit: WAIT! How about this one?http://www.newegg.com/Product/Product.aspx?Item=N82E16817139028
It will cost more initially but I believe if you do the mail in rebate you save money and you get more wattage.