I'm not a video professional, but my feeling is that you'll run into major archiving issues by going tapeless. You'll probably want -- as will your clients -- the ability to archive jobs once done.

With DV tape, you can simply store the original footage that is on the tape itself, along with a data DVD of the FCP project or whatever. That's a cheap way to do it, as DV tapes are inexpensive, as is single-layer DVD media.

With the tapeless route, you'll have to use up to SEVERAL dual-layer DVD disks to burn all the raw footage and FCP project. Restoring projects would of course be much faster this way, but you'll surely be requiring multiple dual-layer disks to accommodate the archive. Archiving and restoring, while faster this way, would be a but more labour intensive across multiple DVD disks of data and footage as YOU swap disks.

If it were me, I'd keep the DV tape and burn the FCP project. If you ever had to restore a job, you could copy the FCP project off of the DVD, pop the DV tape into your camera, boot FCP and have it digitize the tape while you're at lunch (for example).

You might want to get a BIG external Firewire drive for ad hoc backups. You never know when a drive could die, right in the middle of a project and its looming deadline...

 

I agree with what Macaholic has said. I would add that I could understand the need for a firestore if encoding time was somehow limited and you needed something ready in a hurry.
You can Simultaneously record to disk and tape using FireStore according to the web ad.