Hoary pitfalls?

[Samuel Thurston, III]

Everything's been running just a bit too smoothly for me lately, so I
was thinking about trying my hand at upgrading from warty to hoary
tonight on my pentium 4.  Are there any known pitfalls that I should
watch out for?  e.g. packages that are likely to break, hardware
support in hoary that's not in warty or vice versa?

One thing I hope to see is for jack-audio-connection-kit to start
working properly, but I may just be wishful. :)

Thanks,
Samuel