Lowlife = Boring + repetitive
Ravenholm = Nearly crapped myself 10 times
Ravenholm wins.
I agree with your reasoning. For some reason games like Doom 3 (and some other scary games I'm not going to mention here) didn't scare me at all but Ravenholm...well, it took me about three hours to finish it for the first time. I just sat in corners, hugged my blade in gravgun and hoped that the zombies would stop coming for me...
It was the only time I was scared while playing a computer game and I mean truly scared. Funnily after finishing the game a couple of times I was playing Ravenholm to show my friend what HL2 is (the demo is set on Ravenholm) I noticed that I almost finished it in 20 minutes. I was amazed.
*shivers* those fast zombies...you should see how I still react to them in Highway 17.