It isn't an Ubuntu issue. It has to do with the new kernel 2.6.28 and any
distro using it will have the same issues because the kernel now has a
graphics execution manager or GEM. This requires new drivers. Intel knew
this but dragged their heels in getting the drivers out. It may not be fixed
for some time. Ubuntu elected to go with this kernel because it added ext4
as well and kernel 2.6.29 is out but was not ready for inclusion. To stick
with last fall's kernel 2.6.27 when Ubuntu 9.04 is trying to move things
forward would have been silly.

Blame Intel if you feel like blaming anyone. The other graphics cards
manufacturers had the same timelines and they got theirs done.

If you did an upgrade instead of fresh installation, then try booting into
the older 2.6.27 kernel which should still be in your grub list or on your
computer.