Hi,
Recommend GTX960 2GB:
http://pcpartpicker.com/part/evga-video-card-02gp42966kr
You have a pretty nice setup so far so I'm a little baffled that you plan to keep that monitor for 2-3 more years.
For $100 you can get a 22.5", 1920x1080 monitor:
http://pcpartpicker.com/part/acer-monitor-etws0hpa01
As for 2GB and future proofing:
Even at 1920x1080, 2GB can be enough. Yes, there will be games like Shadows of Mordor that can use a lot more however I'd be very, very surprised if a game came out in the next three years that wouldn't run nicely on a GTX960 2GB card if you optimized properly. Any exceptions are probably going to be unoptimized games like when Watch Dogs first released but we'll see. Either way, I have no problem recommend a GTX960 2GB card.
At 1366x768 it's even more unlikely 2GB would be insufficient.
Other:
I suggest you learn to use Adaptive VSYNC for any games that drop below 60FPS on a regular basis. It's too much to go into now, but there are THREE general modes gamers should use:
1) VSYNC OFF
- less lag, gets screen tear to varying amounts
2) VSYNC ON
- more lag, but no screen tearing
3) Adaptive VSYNC ON
- VSYNC ON or OFF is decided automatically (OFF if dropping below 60FPS for 60Hz monitor)
*Why use Adaptive VSYNC?
Because you will get STUTTER if you drop below 60FPS while having VSYNC ON. The best compromise is to have VSYNC OFF which then gets screen tearing.
How to setup for Adaptive VSYNC?
Simply use FRAPS and adjust the quality settings of the game so you rarely drop below 60FPS.
(There's also a handful of games that force 30FPS once you can't output 60FPS. Max Payne 3 and the new Spider-Man game for example. Forcing VSYNC or Adaptive VSYNC in the video control panel will bypass this. So for Max Payne 3 use Adaptive VSYNC then adjust the quality settings so you rarely drop which probably won't happen on a GTX960 at 1366x768 using max settings as I only had to drop a small amount at 1920x1080 though I used FXAA I believe.)