What do you want with the recordings?
- Keep it for a short time (< 1 week), then choose HD
- Keep it for long time (years), then choose DVD
As mentioned before:
If you record it first on HD, later it can be copied to DVD. This option I can advise, because writing direct to DVD, can cause buffering-problems during writing.
The systems you need; you will find them if you know what you really want.
Good luck with your choice.