I quite enjoyed 'Shada' actually and it's definitely a must if you've got the rest, it's the story that almost was but wasn't.
It had more real footage than i expected.
Also i've only seen 'Shalka' on the net but it's really interesting for Grants uptight portrayal and is important because it bridges the gap from the old to the new. Also the trailer makes it look much more impressive on dvd.