There's an i3-4360 in the marketplace
for $120 and a Z97 board from the same seller for $85, that's a killer price and leaves you with a healthy upgrade path for later on. There are a couple other components, boards and a few processors but that one I listed seems like the best for me. Not really much RAM in there but it doesn't cost much at all so I'd just grab a 2X4GB 1600 kit from the egg or whatnot.
For video cards, there are TONS in the marketplace for sale. Also, if you're looking for new there are some good deals to be had. I'd say don't be picky between nVidia or AMD cards, just get whatever is the best price for the performance. I am a huge Borderlands fan and I have played a ton on both AMD and nVidia cards and I can tell you, personally for me, I don't give two flying rat-f***s for PhysX. It's a gimmick and it has never been a selling point for me for video cards. With that said, if you really love PhysX or you just want to try it go for it. There's a GTX 770 in there for about $210 that's a pretty good deal, there's a few R9 280Xs for good prices and I've seen a couple of GTX 680s that might be negotiated for lower prices. If you've got the scratch for it, I would recommend an R9 290, you can find some really good deals for new AND used ones! Their price performance is still fantastic, I run two of them on my overclocked QNIX @ 96Hz and it's a thing of beauty. Regardless, get whichever brand gets you the best bang for your buck, there are some good deals to be had from the great people right here on OCN!