Fear Factory were one of the first metal bands I got into all of them years ago when my taste in music was being forged.
The first album I heard was 'Obsolete' and after a few listens I was hooked and soon explored all of the albums they had out at that time.

They split up after the release of 'Digimortal' (which most consider to be their worst album - or they did before 'Transgression' came out anyway) and not much fuss was made about it - but then after reforming again without Dino and with Christian on guitar and Byron from Strapping Young Lad on bass, they released 'Archetype' - a rather aggressive album and possibly the most extreme album they have done also (behind 'Soul Of A New Machine' and 'Concrete').

The last album 'Transgression' is very watered down and the production isnt great on it at all - I wasnt a fan of it until I saw them tour and perform a few tracks from it live, thats when it seemed to come alive for me.
I still dont think it is anywhere near their best though - and going by some interviews, the band realises themselves as well (with the U2 cover and all..)

If you are interested, here is the setlist I got from the Fear Factory show:
http://i7.photobucket.com/albums/y281/Baz_Anderson/Misc/FFSL.jpg

'Demanufacture' is probably my favorite album by far though, and the first four tracks being my favorites. It seems to be the pinnacle of Fear Factory's lifespan thus far. 'Obsolete' is probably my second favorite and then 'Archetype'

Let me know your opinions on Fear Factory; favorite album, etc. - all are welcome.