You won't need an enormous hard drive for audio, even at 24/28 or 24/96K, but this is a common workflow. With a Firewire box with 8 I/O, you've effectively got a DA 88, and easier to deal with. The echo, M-Audio boxes, and others are all very good for this sort of work. I carry an Echo Layla most places with my laptop.

You won't hear any difference.
You can record to a laptop. One person on this thread (guess who) has recorded thirteen stereo tracks simultaneously (and live) directly into a PC (not a laptop) using Vegas. But you still won't hear any difference.

Stephanie, I've heard from friends in post in LA that laptops are catching on. A lot of my doc will be run and gun around kids, so I have to stay mobile, but I'd go for it on an indie feature.

<<<<You won't hear any difference.>>>>
Actually, you may. Depends on the sound device. DAC's are everything. A soundblaster card won't sound like a DA 45, and an Echo Layla will sound better.
The Mormon Tabernacle Choir was recorded for the Olympics this way, using 2 Laylas, for a total of 16 channels, to a VAIO laptop. We also did the 3 Tenors this way in Mexico City and Monterrey. It's a great way to work, much easier than DAT in the end. But a good sound card is critical. No laptop has a decent soundcard. For a good 2 channel card, there are Cardbus and Firewire boxes, ranging up to 24 channels on one card. At that point, hope that your editing app supports ASIO, WDM, or GSIF driversets.

Stephanie,
I remember working on a similar project myself a while ago, and we to were grappling with the question of to DAT or not to DAT. IN the end we decided against it beause,

1) we couldn't easily find another person to work the dat- (we were a SMALL crew)
2) We couldn't scrape together a budget for a DAT (an FP33 and an MKH 416 aren't great but when they're free they sound oh so much better)
3) We were recording to DVCAM and we decided to have so much extra equipment on a no-budget shoot would just be a bit overkill
4)This was the big one- none of us really were confident in our abilities to sync during post

So we decide to go with in camera sound- granted it wasn't the best choice (but if we had only done the best choice we would have shot on film or HD, and as it was the price was really the issue)

I'm sorry if I upset the sound guru's here just wanted to toss in my two cents, best of luck on your shoot!

I recommend doing both - mixing audio to DAT -and- sending that feed (wirelessly if need be) to the camera. Iv'e used the Sennheiser EW100 to send a wireless feed from my Sony TCD-D10 Pro II DAT to the cam with good success before - plus it also makes a good director's audio feed too. The cool thing about wireless mics like the EW100 is that you can set more than one receiver to the same transmitter frequency, which allows you to feed both the camera and the director. Even if you have to spend a few hundred more to do this on your shoot it is worth every penny. The director will feel more confident and you will save yourself a lot of syncing headaches in post. One of the top most life-sucking tasks is to have to spend time syncing up dialog to the video before you can edit. Even if you send a scratch mix from the DAT to the camera, it's time well spent. That allows you to go into editing a lot quicker and you will save your creative energy for the edit. You can always replace the cam audio with the DAT take once you complete your edit.

- don