Same here - 4wd and then anything in that 30-50 range probably is perfect for most people who don't actually farm. I considered getting a bit crazy and buying a higher hp tractor - 70 or so, but realized it's overkill for anything I'll be doing (and for my wallet). I wouldn't worry about having 50 hp, but really at 40 on my Mahindra, I feel like there's nothing I can't do that I actually want or need to do. Plus, 4wd with a differential lock and it'll go places I probably don't want it to go!
Same here on looking at higher HP. I was dead-set on a 70 HP for the longest time. Now that I see what my 40 HP w/ 4x4 can do, I don't have any reservations.