I had a look at one last year when I was waiting for my JD dealer to pay me some attention - he didn't so I went Kubota.
From what I remember, you can get a Cat 0 three point hitch for the JD 455 - it's an optional extra though. Once you have that then you can do limited things - cat 0 implements are fairly rare. I have seen post hole diggers and tillers for cat 0 though.
I also saw in the literature that there is a quick-attach hydraulic hook-up at the middle of the tractor (hydraulic deck lift etc) that you can run forward and power a snow-blower off.
Finally, you can get a loader for the 455 from JD, but I (and others) would debate the merits of one for the 455. I doubt the frame is strong enough to really do much with it - the tractor is also fairly light and I would worry about tipping it.
Hope this helps ...