here's what comes to my mind:
- if you're ok with a dual-slot card, then go with the NV 8800GTS 512mb. This card runs very quite due to its big but low RPM fan. It's whisper quite.
($160 after $30 rebate)
http://www.newegg.com/Product/...x?Item=N82E16814143119
($129, open box item, no rebate)
http://www.newegg.com/Product/...?Item=N82E16814127325R
- if you don't mind a little disassembling work, then get the AMD 4850 and an aftermarket passive cooler Accelero S1 Rev2 (about $30-$35). This requires a bit more work and probably will void your warranty, but it's a little faster than the 8800GTS 512mb in gaming, but since you only do minimal gaming, then just get the 8800GTS.
($158 after $30 rebate)
http://www.newegg.com/Product/...x?Item=N82E16814121253
($169 after $20 rebate)
http://www.newegg.com/Product/...x?Item=N82E16814129112
Don't forget to add the price of the Accelero cooler if you truely want a quite AND cool running card. This is almost a must for the 4850. Otherwise, expect the stock fan of the 4850 to be pretty loud when the temperature ramps up.
If you want a cheaper solution, around $100, there are cards there too, like the 8800GTS 320mb, or 8800GS, or any of the older AMD HD 2xxx series card. I don't know these lower cards too well, but I'm sure they're cheaper. But keep in mind that these cards here are at least a generation older, and they do run slower, and if they're the single-slot type, then their fans are most likely going to run loud!
IMO, if you don't care for gaming much, I would get the MSI open box item above for $129, without any rebate to deal with. Newegg's open-box item are pretty reliable. If you're ok with tinkering with hardware, then the 4850 + Accelero combo is nice deal but will go over your $175 budget a little.
Also, if you can wait a month, then wait, because prices will drop more then since Nvidia will be realeasing their newer card around Aug. 22nd, and since NV and AMD are in a price war, I expect some more price drop, but the drop will be more for those cards costing well over $250. The 8800GTS 512mb probably won't see any more drop, and 4850 can go a little lower, maybe $20 lower, but don't expect much more drop for these two cards, so heck if you can't wait, then just go ahead and get them now.