nice topic to choose MattTheMan, the book is a really good read and gives a nice 'different' persective to the film (i.e, using your imagination).
The first one does look giger'esque and in fact he did a bit of concept work for the film but parted from them over some disagreement or other projects (cant quite remember)
The basic shape should be straightforward and it would be nice to see the mouth rigged if you're going for the film look. The texturing or extra detail on the giger reference would
give the creature a lot more character.

Good luck