That's really odd that I have come across your post. I was looking for something else but what you are experiencing is similar to something I have had happen to me. I downloaded and burned what I thought was Ubuntu 11.04 but when I booted to the disk it was backtrack5. How this happened is beyond me. I realize this is similar and not of much help to you. I'm just making conversation so far.
OK regarding your boot method. Which of the default modes have your tried. I have not been able to get the GUI to boot via the first choice it offers, but I have been able to get the GUI to boot via the forensics choice. The only frustrating part of about that is that I am unable to save anything to my USB drive even after changing various mount settings. I believe this is due to the no drive no swap feature for forensics. But the Text only choice leaves me without a GUI. GRRR....
Maybe I downloaded a bad ISO or have yet to find the correct boot command to have all the features of forensics and the ability to save work onto my USB for later use. Have a great day and if you have any ideas for me let me know and if I find anything that can better help you then I will get back to you.
Oh and I just realized what you may be experiencing could be due to your ISO version is it Gnome KDE or Fluxbox? I am unable to say for sure but it sounds like a Fluxbox due to the lack of graphics and themes.