Recap of the video card recommendations with a twist - I think it's silly to make recommendations $10 apart so I'm going to condense their recs to a smaller list.
With Fans and with a gamer attitude
Best under $50 AMD 4650/4670 depending on where and when you buy it.
Best under $100 AMD 5670
Best under $150 AMD 5770
Best under $200 AMD 6850 or Nvidia GTX 460
Best under $300 AMD 6950
Best under $400 2x AMD 6850 or 2x Nvidia GTX 460
Best under $500 2x AMD 6870
Now with my personal opinion tossed in the mix from a SPCR attitude of noise we can't just name chips we have to be specific on the card to be sure you get a quiet or silent card.
Fanless or with almost silent fans and a gamer attitude
Best under $50 none
Best under $100 PowerColor Go! Green 5570 GDDR3 or HIS Silence Radeon HD 5550 GDDR5 and either one will be slower than the $50 choice from the list above
Best under $150 GIGABYTE Silent Cell GV-R575SL-1GI Radeon HD 5750 (no Displayport)
Best under $175 PowerColor SCS3 5750 or MSI R5770 Hawk Radeon HD 5770. MSI Hawk 5770 is very quiet for a fanned card, PowerColor 5750 is fanless but not as fast at gaming. Most die hard SPCR types would choose the fanless option. Why pay more vs the Gigbyte silent cell 5750, at this price point you get Displayport.
Best under $200 GIGABYTE Silent Cell GV-R577SL-1GD Radeon HD 5770 or PowerColor Go! Green AX5750. The Go green uses less power and will fit in smaller cases but the Gigabyte is a faster gaming card. Both are silent.
Best under $300 None
Best under $400 None
So what if you want something faster than a 5770 that is silent. Either wait for a fanless 6xxx card or Buy a AMD 6850 and replace the stock heatsink with something that will turn the card into a 3 slot solution. No factory card fits the bill yet but new cards will come.
Note all this is written from a retail perspective. If you need a cheap silent card you might want to look at the Lab Samples Clearance
. Last I checked there was a video card or two there.