I've hear that a smaller 4wd performs similar to a 2wd tractor 20-30% larger.
That % puts you close in the hp range.. but there is still the money issue.. and the pto hp issue. Just have to decide what you want.
If you are getting a front end loader... as much as I hate to say it.. I'd lean toward the 4wd. ( When I say 'hate' to say it... what I mean is I generally try to by the largest tractor I can for my money, but not too large for the task.. etc .. excess HP is never wasted. )
A word of advice... these tractors are too light to make use of the hp they have.. even the 4wd ones will easilly spin in soft material when pulling a load. Don't get me wrong.. big ones get stuck too... My 4wd NH 1920 ( 33hp 3500# ) got stuck in a dry -looking- pond bed... sunk down to the axles in muck..
If you aren't doing loader work... I'd get a larger 2wd.
There are other factors to consider.. like terain.. if ya gots lots of hills.. then I lean back to the 4wd... gives you some breaks via the drivetrain connection when going down hill.
Let us know what you plan on doing with it, and your area.. etc.
Soundguy