Slight trouble with my recent Mint install on a Compaq Deskpro (1000MHz P3, 512MB RAM). Once it gets to the graphical boot screen, it just chills there for a little bit. The progress bar doesn't move, the hard drive indicator light doesn't blink.... it seems like nothing is happening. This goes on for about a minute before the boot-up process resumes like normal. The system works flawlessly once it's up.
I disabled the "quiet" boot parameter in GRUB, and it seems that it is hanging up on the section labeled "Waiting on root filesystem".