Wouldn't a pair of NGT-1's work great for a stereo setup.l
Stereo setups with shotgun microphones can be a bit trickier than with some wider pickup microphones, but you could record a mono shotgun and pan it (to both the left and right channel with a balance you like) in post.
For some situations, you might look at the The Rode NT1-A http://www.adorama.com/RDNT1A.html which has a good budget reputation. I believe Rode has replaced or complimented it with the NT1 http://www.bhphotovideo.com …d_cardioid_condenser.html You might also consider one of these two (Rode also carries a matched pair of the NT!-A) microphones as another tool to have access to.
this is gonna get expensive lol
How about a couple of http://www.bhphotovideo.com …H_8070_MKH_8070_Long.html
Keep in mind that while the microphones I have mentioned are good microphones for the prices, microphones, just like lenses, can get a lot more expensive for really good ones.