Yeah I have used Maple for graphing and solving triple integrals. I used Maple 7 and I'll bet there is a new version out by now.
Also try Mathematica (I think that's what its called)
It is not very well known but Atlantis 2000 is a software package primarily for engineering math and I have seen some wonderful three dimensional graphing on there.
As for general Mathematics software I agree with the Wiz, Maple from waterloo is very very good.
I just checked and there is actually Maple 9.5 out right now.
By the way I heard recently on NPR about a 3D graphing program for the macintosh. It was a really amazing story about how 2 workers who were fired kept coming to work secretly finishing this graphing software and it turned out to be a big hit! Has anyone seen or used this program? I don't have a mac so I've never seen it.