I'm no expert but i would dedicate the 80 gig drive as your system drive. I would have the OS and alll the apps and related files here. The larger drive I would use as my "audio" drive and here I would put all my sound files and sample libraries etc. When you can afford to do so I would recommend another drive to be dedicated to backup.
drde - I am a newbie on the forum, too. But I have some experience in hard drives. One important issue is the latency of the drive. Too high, and you will start dropping out on recording and sampling.
Latency of the drive is determined by 3 things (well. more than 3, but these matter most in audio):
1) head seek time: a good audio drive should be in the 8 to 10 ms range
2) drive control type: SATA is good; External Firewire is good; SATA RAID 0 is great; IDE and SCSI are pretty old these days, and not as good.
3) how much other "stuff" is happening on that drive. It should be reserved for audio I/O only, no programs, O/S, swap space, etc.
I bought an external Firewire drive, from Rocstor, which has nice speed, and is very easy to install, but it is _noisy_, so you will want to have it in a closet or something.
If you are running out of drive headroom, and don't want to spend more money right now, you can always put less stress on it for awhile, by reducing the sampling rate, say down to 44.1kHz.
If you run out of a 250 GB sample drive fast, you will run out of money even faster.
LOL !!... I guess I should have added ......"if you have the money " ...
With these group buy's going on, it's hard NOT to spend your money !!... The programs are just getting better and better, and less expensive to buy !!....It's virtually a good time for all of us !!....Jim