Gothboy,
Where to start? Well, I have a Firmtek 1V4 attached to a 500GB Hitachi Deskstar 7200 RPM 16 Mb cache. So lets start with the hard drive. SATA ia a plus for the afore mentioned cabling issues but also the 16 Mb cache found in most BIG drives gives a nice performance increase. Also, the big drives are going to fill up slower and therefore stay at peak performance longer ( The fuller a HD gets the slower it gets) and a 500 GB drive can be had in the sub $200.00 range (I gave 168.00 for mine shipped). This isn't much more that a good PATA drive these days. However, the speed difference isn't going to be that much better since SATA 150 is actually 1.5 Gbits/sec. This translates to approximately 180 Mbytes/sec (more on this later). As a last point, the Hitachi deskstars use less power than some other drives ( Run a search, there are some great reviews out there) and have legacy (Molex) connectors. This isn't a big deal as Molex/SATA power adapters are cheap but it does keep things cleaner.
So, on to the controller. As Rodney stated Firmtek makes the Sonnet card so either is a fine choice. The big plus for either of these cards is that they don't need software to run them and therefore can be used to control a BOOT drive(this is what I run, OS X opens so much faster). You have lots of options here (two drives or four or four internal +four hot swappable external) and your needs and budget are the only deciding factors. As for my choice? The fact that Firmtek spent about an hour and half talking with me before I even bought the controller and then hooked me up with a sweet deal on the drive clinched it for me. Do some research and you can't go wrong. There are a few minor issues to be aware of but a quick call to the card maker of choice will set you on the right path. That's my $.02. Good luck.
Cheers,
Chris
P.S. Most SATA drives these days are SATA 3.0. While this kind of speed is a pipe dream in a G4 (Not enough bandwidth on the PCI slot) the drives autoconfigure (SATA 150) and when you get that NEW shiney Mac Pro( or PPC G5) your drives will throttle right back up to SATA 3.0. Oh and like Rodney states, these are theroretical burst rates, not real world numbers.
1.4 GHz "digital audio",1.5 GB RAM, 500 GB SATA (OS X) Mac OS X (10.4.8) Pioneer DVR-111D,FirmTek SeriTek 1V4, BFG 6800 GT oc
1.4 GHz "digital audio",1.5 GB RAM, 500 GB SATA (OS X) Mac OS X (10.4.8) Pioneer DVR-111D,FirmTek SeriTek 1V4, BFG 6800 GT oc
1.4 GHz "digital audio",1.5 GB RAM, 500 GB SATA (OS X) Mac OS X (10.4.8) Pioneer DVR-111D,FirmTek SeriTek 1V4, BFG 6800 GT oc
1.4 GHz "digital audio",1.5 GB RAM, 500 GB SATA (OS X) Mac OS X (10.4.8) Pioneer DVR-111D,FirmTek SeriTek 1V4, BFG 6800 GT oc
1.4 GHz "digital audio",1.5 GB RAM, 500 GB SATA (OS X) Mac OS X (10.4.8) Pioneer DVR-111D,FirmTek SeriTek 1V4, BFG 6800 GT oc