in gerneal i find linux's support for some 'hardware pata/sata' *edit* controllers to be very poor. specifically in the area of booting of a raid array. now, if you have a 3ware controller, supposedly its a different story. i dont know first hand. as for non boot partitions, i dont think youll have much of a problem.
as for filesize i think that may depend on the filesystem you use.
here is some specs for reiser4
XFS specs
do your own gogle search for any other file system you may use to find its technical limitations.
i dont know about DVD writers as i dont personally have one. im sure they are supported though. the following link may be applicable to you.
http://fy.chalmers.se/~appro/linux/DVD+RW/
search these forums for DVD writing support too.