I am a fan of the green paint....but that is because I have one (and love it) and secondly, in my area every town big enough to have a McDonalds has a Deere dealership, so parts and service are at every turn should I need it. When I was shopping I also found that the green paint wasn't significantly more expensive than what I would call the other top tier brands either. You hope you never need the support of parts and service, but it certainly is something you need to consider in my opinion.
In my opinion...must haves for a tractor:
If you need 40hp....get 45 or 50 if you can afford it. Very seldom do people want a smaller tractor.
Front end loader is a MUST have.....they are as handy as a pocket on a shirt.
Front wheel assist and a rear dif lock are a MUST have....power is worthless without traction.
Industrial or ag tires for real work.....unless you simply want an oversized lawn mower. See my comment about traction.
Cat 1 hitch....most are pretty standard now.
Traction is VERY important when working in the snow, doing tillage or on slopes. Nothing will frustrate you more than having all that power and it's simply wasted on a spinning wheel and your stuck, can't do what you want or worse something slips and something bad happens. Weight has a place in the traction discussion as well. You don't need to focus on it, but there is some advantages (and disadvantages) to a heavier machine as well.
Shop around when the time comes and see what you like the best. A good machine should be a once in a lifetime purchase so get what you want and need for the long haul. I will warn you that if you have a trailer for it.....you will be surprised just how many "friends" you have that have a need to borrow it as well.