Gpu budget increased, 760 4gb or 770 4gb?

Well let's see here... the GTX 770 costs at least $385 (The price in-cart):
http://www.newegg.com/Product/Product.aspx?Item=N82E16814500301
The problem is, that card only has 2GB which will be a major bottleneck in a year or so (according to AnandTech). There is no GTX 770 3GB so you would most likely want to get the GTX 770 4GB which starts at $440:
http://www.newegg.com/Product/Product.aspx?Item=N82E16814130945
Now that's a HUGE chunk of change to spend when you consider that the Radeon HD 7970 GHz Edition has 3GB, is tied for the GTX 770 in performance and only costs $300 (-$20):
http://www.newegg.com/Product/Product.aspx?Item=N82E16814127732
Now before some nVidia fanboy starts spouting off that the GTX 770 is so much faster than the HD 7970 GHz Edition without actually having a clue as to what he's talking about, I'll let someone who is renowned for his knowledge of computer hardware, Anand Lai Shimpi (AnandTech) speak for me:
" This current generation of video cards has been something of a rollercoaster ride in both performance and leadership. In the last 18 months we’ve seen AMD take the lead with Radeon HD 7970, unexpectedly lose it to GeForce GTX 680, gain it again with Radeon HD 7970 GE and greatly improved drivers, and then break even in the end with GTX 770. GTX 780 and GTX Titan make all of this moot with their much greater single-GPU performance, but priced as they are they’re also nowhere near being in the same market segment as the GTX 770 and 7970GE.

In any case, more than anything else it strikes us as particularly funny that we’re once again looking at a tie. That’s right: on average GTX 770 and 7970GE are tied. GTX 770 delivers 102% of the performance of 7970GE at both our high quality 2560x1440 and high quality 1920x1080 settings. Of course as with some of the past battles between AMD and NVIDIA in this segment, these cards may be tied in our benchmarks but they’re anything but equal.

After all is said and done, the GTX 770 ends up beating the 7970GE at 6 games, while the 7970GE takes the other 4. Meanwhile within those individual games we’ll see anything between a near-tie to a very significant 20% advantage for either side, depending on the game in question. This is very much a repeat of what we saw with the GTX 680 versus the 7970GE, and GTX 670 versus the 7970.

Our advice then for prospective buyers is to first look at benchmarks for the games they intend to play. If you’re going to be focused on only a couple of games for the near future then there’s a very good chance one card or the other is going to be the best fit. Otherwise for gamers facing a wide selection of games or looking at future games where their performance is unknown, then the GTX 770 and 7970GE are in fact tied, and from a performance perspective you couldn’t go wrong with either one."
http://www.anandtech.com/show/6994/nvidia-geforce-gtx-770-review/18
With that said, maybe you should be looking at the red team this time around. Oh and don't forget that lovely AMD "Never Settle Gold" gaming bundle that's included with every HD 7970 and allows you to choose 3 current games from its large selection. Happy gaming!