Jroutma is right, i'm 100% satisfied with my SCSI config.
A bit of background. I've owned HDDs since 1989, when 4MB was "huge". Back then SCSI was the only way (i had an Amiga). Then came the PC and IDE drives. The first thing i noticed was, IDE drives were *slower* than my previous SCSI drives... not good. So i eventually came back to SCSI by the means of an Adaptec 2940 (had to earn some money for it, so it took some time...).
Now i've got the 29160, Ultra SCSI plextor units, Ultra160 HDDs - and i'm waiting for the Seagate Cheetah 15K.3, the fastest drive in existence...
In the meantime i'm still on IDE drives at work. I can *feel* the difference. The OS is less snappy, i'd say "sluggish", drive accesses lock up the machine, and HDD units die like flies on a window in summer.
Each time i get back home (set aside the watercooled experience) it's like i'm "back to the future"

Quick OS loading times, instant program launching, pain-free *swap file accesses* (!! the most noticeable !!)... In those games where data is fed more or less continuously from the HD, no hang-up...
Add to this, the mechanically superior units (=longer life times), easy setup in OS (nothing to do...), no chipset / driver problems (ive got the infamous KT133) since only the Adaptec has to be known by the OS - and Adaptec drivers are standard in every OS.
Besides one can find rounded SCSI cables - at a price though.
So may i get back to ATA or even Serial ATA ? I dont think so, and the current trend from manufacturers confirms this choice...
(edit)
BB2K, if you got the U160 way, forget the RAID. Unless you *really* need the mirroring security (ie you're running an enterprise-class server) it's a waste of money, heat, and case room. The latest 10K units (Cheetah 10K.6, Atlas 10K.4, Fujistsu MAM) or 15K units (Cheetah 15K.3, upcoming Atlas, Fujitsu MAN) are so blazing fast that you dont need the added speed of RAID striping.
If it's for your personal PC, stick to a single A29320 (since the 160 is gone...) and 1 or 2 good HDD unit(s). I'd say, a small 15K for the OS and critical programs (=games), and a big 10K for data storage and other programs.
(/edit)