That's going to be tight at $175. ITX boards demand a premium right now. One way to go would be this board:http://www.newegg.com/Product/Product.aspx?Item=N82E16813131878
...and this processor:http://www.newegg.com/Product/Product.aspx?Item=N82E16819115078
A bit over your limit, and you would still need a gfx card because the on-die GPU is not very good.
You might be interested in going the APU route instead. Go with this board:http://www.newegg.com/Product/Product.aspx?Item=N82E16813157340
...and one of these processors depending on your budget:http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=100007671+600166681+600372025&QksAutoSuggestion=&ShowDeactivatedMark=False&Configurator=&IsNodeId=1&Subcategory=343&description=&hisInDesc=&Ntk=&CFG=&SpeTabStoreType=&AdvancedSearch=1&srchInDesc=
You wouldn't need a discrete card, because the APU contains a good on-die GPU for gaming at 720p or less. And you can always add a discrete card later if you want to.