I remember someone mentioning about dialup modem detection issues. I had the same problem: my first boot into FC1, kudzu popped up saying my dialup modem (a plain old external 56kbps modem hooked via DB9 serial cable) has been "removed". I selected remove config in kudzu. Then I tried to setup dialup networking through the network device control GUI tool - and it too could not detect the modem. After putting in the /dev/modem symlink to /dev/ttyS0, and manually configuring the things in network device config GUI tool, I was able to get the link up and browse. After rebooting, kudzu again popped up saying it has "detected" my modem. This is weird.
Other problems I have had are:
1. changed initdefault to 3 (non-X startup), and I could see
a lot of "modprobe could not locate device block-major-XX-YYY"
messages during boot.
2. I see an error message printed right after entering interactive setup
saying /=LABEL partition/file doesn't exist or something. I don't
know the exact message because it scrolls by too fast.
My machine is a Athlon-2GHz, with VIA KT333 chipset ECS motherboard and 256MB DDR RAM. I have been using this machine with my RH 7.3 setup for a long time w/o problems.