I can't use any of those bench press or overhead press machines because my wrists are seriously ruined from gymnastics in my youth (damn pommel-horse). I have really inflexible wrists that also cannot rotate smoothly.
But I have absolutely no problem doing barbell or dumbbell exercises where I have control over the angles. I would suggest to anyone starting out to avoid machines if at all possible.
I used to work out a while back, 3 to 4 times per week, and one of the things that made me stop (besides boredom to be frank) was that I felt quite a bit of pain in the wrists. I've kept that exercising schedule for 4 months at a time, but the pain didn't go away in those periods. My thought was that I was damaging my wrists in some way.
How long was it until you stopped feeling numb? Did you use any restraining device (gloves or something like that) while working out?