GPU at a $100ish budget

Hey guys, building a new rig soon, but I cant decide on a gpu to put in it. I've havnt really kept up with new hardware so im lookin for some help. Basicly lookin to use this as a casual gaming comp. I'm not really stressing to much on running the games at max settings and highest fps, as much as I just want something that can run smooth on decent settings. Heres what I plan on buying.

CPU = AMD Phenom II X6 1055T (Thuban) 2.8GHz 6 x 512KB L2 Cache 6MB L3 Cache Socket AM3 125W Six-Core Desktop Processor

Motherboard = ASUS Socket AM3 AMD 785G HDMI ATX Motherboard (Model: M4A785TD-V EVO)

RAM = G.SKILL Ripjaws Series 4GB (2 x 2GB) DDR3 1600

PSU = OCZ ModXStream Pro 700W ATX12V v2.2

As for games just lookin for something to run WoW, League of Legends, and Call of Duty Black Ops

nvidia gtx450 or
amd hd5770

Kinda hard to find any of those within my budget, would this be a nice substitute? http://www.zipzoomfly.com/jsp/ProductDetail.jsp?ProductCode=10011638

http://www.newegg.com/Product/Product.aspx?Item=N82E16814130572

or

http://www.newegg.com/Product/Product.aspx?Item=N82E16814127476

go with that 5750 or this http://www.newegg.com/Product/Product.aspx?Item=N82E16814150482

I would personally go for an HD 5770 or GTS 450.