I could have sworn this list was on this site, but alas it wasn't. Now I'm not sure how to do this one, whether I should go foreign and English, or maybe even group by year or alphabetically. For now however I'll just go with ten, and I'll add as I see fit. 

Although some films may have not been released in the US in the 90's, I'm going by international release dates, because it just makes life easier.

1. Pulp Fiction (Tarantino)
2. Schindlers List (Speilberg)
3. Goodfellas (Scorsese)
4. Before Sunrise (Linklater)
5. Dances With Wolves (Costner)
6. Magnolia (Anderson)
7. Fight Club (Fincher)
8. Malcolm X (Lee)
9. L A Confidential (Hansen)
10. Natural Born Killers (Stone)

This was my list as of about a year or two ago, so not much changing. So here's an off the top of my head list of foreign films from the decade.

Flowers of Shanghai (Hsaio-Hsien)
Europa Europa (Holland)
After Life (Kore-eda)
Rebels of a Neon God (Ming-Liang)
Happy Together (Kar-wai)
Underground (Kustirica)
Satan's Tango (Tarr)
Hard Boiled (Woo)
To Live (Yimou)
Ulysses Gaze (Angelopoulus)