Are 3 LOR's truly necessary?

[ghil04]

I've seen most people say that 3-4 are recommended, and that a lot of schools take up to three. 

However, how much will it hurt me if I only have two and choose not to submit an optional 3rd? I'm thinking zilch, but could use your guys' guidance.

[Shark Week]

I'm also going with two recs. I have two professors who've written truly epic recommendations; I could get a 3rd, but it wouldn't be as good as the two I already have and I haven't seen any schools that require three. I seriously doubt it's going to hurt.