I ditto what yelbike said, and don't forget about financing. Due to most people not having all the cash on hand they have to drop the price greatly in the first couple years a tractor is old, then it evens out. A 3 year old tractor may drop 25% off of sticker, but a 10 year old tractor is only about 35-40% off MSRP. If you can pay cash, and have an excellent deal on a low hour, used machine, it will benefit your pocket book a lot to not have to pay the extra.
I am a believer in new is the best... and I say that as I bought a used tractor 3 days ago. Fit my budget better (a lot better, like $25,000 cheaper) and was in good condition. Now I gotta sell my tractor though...
Deere's builder isn't always the greatest. 2520 definitely has a loader, just looked it up, went in through attachments. 200CX lists at $3,305, 200X is $2,621. I feel the extra power and quick attach/detach is worth it for the CX though.