While Cloverfield is far from being a 'Lovecraftian' movie in any purist or canonical sense, I did feel that at times a Lovecraftian mood was nicely evoked. The monster itself being a case in point.
Although not explicitly Cthulhoid (whatever that means) I've noted that the monster has been described variously as 'weird' and 'creepy' on some of the internet forums about which I've been lurking of late. Indeed, these do seem apt descriptors: although not entirely unanthropomorphic the beast does have a rather curious - one might even say 'strangely angled' - anatomy and mode of locomotion, attributes suggestive of its 'outsideness'. Certainly the monster is a bit different from what one usually encounters in the standards of the giant-monster-on-a-rampage movie genre. This on top of what I felt was already quite a 'weird' movie, where an intrusion of otherness leaves a trail of chaos, confusion and ambiguity where nothing is fully or satisfactorily explained. In turn, this leaves plenty of scope for the play of the imagination and the mapping of one's own vague fears and terrors onto the tabula rasa of Cloverfield's monster(s).
Interestingly, after I'd seen Cloverfield a number of friends expressed their concern about watching a monster movie where one never actually gets to see the monster. In actual fact (and as should be evident from the above), the monster is seen on a number of occasions (especially toward the end of the film). All in all, the revealing of the monster is handled rather expertly and in what I took to be a very Lovecraftian fashion: you do get to see what it looks like, but the shaky-cam gimic means that it is never revealed too clearly or for too long - somewhat akin to Ridley Scott's strategy in Alien. That is until very close to the end of Cloverfield where the director has seen fit to go for a close-up of the beast - presumably the film's 'money shot'. Here we are given a very clear view of the thing's torso and head (and in full daylight). Whether this was supposed to evoke horror I can't say, but at this point Cloverfield departed from what was presumably J.J. Abrams' original vision, and in doing so nearly ruined the movie for me. In revealing everything, you invariably reveal too much - in this case something like the hybrid bastard of the Rancor from Return of the Jedi and the Honey Monster.
So, Hollywood still seems a long way off from producing the quintessential Lovecraftian movie (and as the HPLHS' version of Call of Cthulhu demonstrates, maybe Hollywood isn't the right place to be looking anyway). Still, assuming it gets green-lighted we at least have del Toro's touted At the Mountains of Madness to look forward to a few years hence.