Well, first off let me make a broad reccomendation. If you are going to film school, don't buy a camera yet. Most likely your school will have great cameras (far better then the price range you are suggesting) and you can use them. I am assuming you want the cameras to try for personal projects.
If you do want your own to practice with and you are going to school, try to get something with a true lens system, like the Canon XL1 or XL2 (the XL2 is new and very expensive 5000, but you can get used XL1's on ebay for 1000)
A true lens will teach you a ton about optic and the like. Other prosumer cameras have lenses with mostly digital optics.
Also, make sure the camera you get is 3 chip camera, otherwise you will kick yourself. And having XLR inputs is a great idea, but it all depends on what you will be using it for. If you are shooting short films or even features, chances are you will never be recording sound into the camera, it will be recorded sepreately.
I don't know those cameras you have suggested except for the GL2. It is a good camera, but still doesn't have the top of the line features you'd expect for "film making". Films you have seen in the theatres were shot in the XL1, beacuse of hte interchangeable lenses.
I own a Panasonic DVX-100a and while it is 3500, it is a great camera. It shoots 24p and have xlr inputs, but I whish it has interchangable lenses. Most of the newer cameras have 24p, but they will be more in the 3000 or higher price range. 24p is what will give you the "film look" as it shoots at film speeds. THey also usually have filters in the camera that make a "cine" look on the video itself.
good luck and have fun!