In my experience suspend/hibernate is highly dependent on the kernel modules running on the system. Specifically this means the proprietary nVidia or ATi video drivers. On all my systems if I'm using a crappy FOSS driver suspend and hibernate work spectacularly well. As soon as I turn on the proprietary drivers it mucks it up. My laptops with integrated Intel graphics seem to all work pretty well on the included drivers, presumably they are FOSS or at least binary blobs that Just Work.
Does this shed any light?
Maybe your problems are related to the new version of Xorg in 9.04. The existing proprietary drivers don't support it. It was the same way when 8.10 was released. :/
It seems like Ubuntu represents a significant-enough percentage of the Linux desktop market that nVidia and ATi should play along with it, especially given its dependable release cycle. Furthermore Canonical should be thinking about these types of external dependencies come release time. They can't tackle Bug No. 1 if every six months the graphics subsystem for the newest release is broken for three months.
At a deeper level, methinks the three big graphics vendors should really become involved in Xorg, guiding its development with devs and a little money to give their Linux desktop and workstation customers a better user experience. It brings to mind the whole circular dependency notion of Linux having relatively low desktop adoption due, in part, to poor support for some hardware. However, the hardware manufacturers who write the secret drivers for the aforementioned hardware won't give the Linux market serious attention because it has low desktop adoption.
We could all use LTS releases which stay around long enough to become stable and mature, but the fast-changing Linux marketplace really puts an emphasis on having the newest, coolest stuff.
I pray to all things holy that Larrabee brings about a new graphics paradigm that will quickly and easily sweep away all this proprietary, poorly documented, NDA-bound hogwash. Though x86 is not Free, it is at least well-enough understood that FLOSS developers could kick some serious butt with it right out of the gate.