HDD/DVDRs are ideal if you want to make editted recordings that play on other DVD players.
If you buy a standalone DVD recorder you can either record in Video Mode or VR mode. The former is compatible with most DVD players whereas the latter is incompatible but offers editting, timeslip, chasing playback, playlists etc. Adding a HDD into a DVD recorder means you have the benefit of VR mode (i.e. editting, non-linear playlists) but can easily dub to DVD-R in 'Video' mode which will play on virtually all DVD players. Plus, as the HDD has greater capacity than any DVDR, you can record in best quality mode, edit and then dub to disk without wasting any space on the disk (which would require you to use a lower bitrate and thus reduced quality).
In summary then if you can afford it buy a HDD/DVDR combo as this is the perfect type of machine to accompany Sky+. Ideal machines to look at would be the
Toshiba RDXS32 or the
Panasonic E95.
Needless to say if you are prepared to author on your PC then you can get away with a standalone DVD recorder (although I would still recommend a HDD/DVDR combo). With such a machine you can record in the incompatible VR mode, import onto your PC, author and burn to DVD-R (see
this guide for example). Suitable machines include the
Panasonic E65 or
Pioneer 320. If you can push the boat to a HDD/DVDR though do so!