Look at a Geared head unit with a dove tail column if you can. The dove tail column is a lot more rigid and you will get a better finish. That being said the round colomn has it's advantages in that it alows you to swing the head left and right and cover more of the table. Also most of the geared head units allow you to tilt the head left and right where the belt drives only work straight up and down. This can be very useful on a lot of jobs once you get the hang of using a mill.
My first mill was a geared head bench top machine and I did a lot of stuff on it. I've got a pic of it some where. They are a lot of fun to use and you will amaze yourself at the things you can make when you set your mind to it.
Grizzly seem to have some reasonable Chinese and Taiwanese machines for good prices in the US
http://www.grizzlyindustrial.com/pro...spx?key=480000
I enjoy using the mill so much that I've moved on to my 3rd milling machine now. I replaced the bench top unit with a big old turret mill that I restored.
This thing probably weighs 2 tons and stands 7' tall.
Restored and in the workshop
In the last month or so I sold the old turret mill and bought a brand new Taiwanese machine. This thing is awesome. I thought the old turret mill was great but this machine makes the old one look like a dinosaur.
It's got a much bigger table and more travel in every direction plus the 3 axis Digital readout makes machining dimessionally accurate parts easy.
You need a bit of floor space for one of these bigger turret machines but you can pick up some bargians with 2nd hand industrial stuff. I reccomend getting the biggest machine you can fit in there/afford. As an old machinist friend has often quoted to me "You can do a small job on a big machine but you can't do a big job on a small machine"
What ever way you go, milling machines are a lot of fun and satisfying to use. Every home fabricators workshop should have one.
Cheers