Go Intel, quad core.
1 gig RAM?  That's nothing.  Go 4+.
512meg vid?  That's light.
80 gig IDE HD?  That's lightweight and a bit behind the bus-times.  You'll fill that up in no time at all.

The only thing that isn't something that was considered average-to-decent 4 years ago on that list is the dual core.  Those are a bit newer.  Everything else is behind the times and you wouldn't even have to get expensive or cutting edge to get a giant increase in performance by just stepping up a couple of levels.

I'll leave the specifics to others who have been familiarizing themselves with the current market. I haven't.  The computer I'm on is about 5-6 years old and it has better stats than the one spec'd out above with the exception that I don't have a dual core processor.

My advice would be that you could get a significantly better system for an extra 30% more money.  If you can't afford that now, save up a bit more.  Could the system you spec'd run Poser?  Sure it could.  Mine does.  But, it'd be a waste of your time unless you absolutely HAD to have a new system now and couldn't afford to spend any more on it.