there are a lot of good am3 boards at/under $100, no reason to drop $150 unless you want/need usb 3 and/or sata 3, especially since that board won't support bulldozer. furthermore, i dunno why you're looking to drop $140 on a phenom ii x4; it's really not worth it seeing as bulldozer is right around the corner :\.
there is really not a good reason to drop $300 on a platform that's on its last legs. i would really say try to tweak your build so that you can get an i5 750/760, but since you've got a hard on for amd there are 2 options i would suggest to you:
1. just wait for bulldozer (idk if it'll be out by may, but the way i understand it, it will not)
2. buy a cheap(er) amd mobo/cpu now that won't depreciate too much by the time bulldozer comes around, then sell the combo and use that cash plus the cash you save now by buying the cheaper stuff in the first place to upgrade to a bulldozer cpu/mobo.
quick look at combo deals on newegg:
http://www.newegg.com/Product/ComboD...t=Combo.592418
solid processor, definitely enough for gaming at 1280x768; i used to have a 435, which is the 2.9ghz version of this chip, and it is indeed a very capable cpu. since this combo is the exact price of the cpu you are/were looking at, this option would save you the cost of the motherboard you're looking at, ~$150, that you can put toward a bulldozer upgrade. and, i know i'm risking being a heretic here, but honestly there isn't THAAAAT much of a difference between an athlon ii x3 and a phenom ii x4, at least in my experience (unless, of course, you're doing a lot of heavy multitasking). *especially* compared to the difference that bulldozer is going to bring.
you could save more money by buying a used cpu/mobo here on anandtech, but i understand it's just not quite the same as buying new parts.
also here's a $15 cheaper case
http://www.newegg.com/Product/Produc...82E16811129066