something with 48v phantom power & a XLR to mini adapter.
something like a beachtek would work (they had another model, that looks like it is discontinued, but should be easy to find) http://www.beachtek.com/dxaslr.html
though for all the praise a NTG-3 has gotten, I think you'll lose a lot if you don't have good pre-amps behind it. so if you want really good sound, get a good field mixer, but by the time you spent $1k on the mixer, you should also spend the $ on a recorder with XLR inputs...
Kind of depends on how you plan on using it. Out in the field in some crazy run-n-gun environment I'd go with a juicedLink. However, for a documentary, indie film, educational, or corporate type video, I'd want some bigger knobs and brighter VU meters in a high quality field mixer. So then it comes down to budget. Something like a Signvideo ENG44, PSC DV Promix would be my choice at a minimum for gathering high quality audio consistently. Explore the Sound Devices site too, if you'd like to read up on the high end gear. A used Shure FP33 might also pop up on eBay if you have time to wait it out. If you don't need battery power, and can run on mains (AC) go for a small Mackie mixer.