Hardware raid 5 is the way to go for speed, reliability or dependability.  If 
you want cheap raid 1 or raid 5, you can do hardware IDE raid.  It will be the
wave of the future.  As far as I know, most software raid packages will not do
things like rebuild on the fly or fail over to a hot spare.  Also with software
raid your computer will lag like a 386/16 with the turbo button off because it
has to calculate what should be on the failed disk while in failure mode.
Hardware raid has onboard processors which pick up this overhead.  Check out
the 3ware review I did a while back ago, you can get this IDE raid card for 
about 100 bucks these days.  It is definately worth it!

Mike