Basically, they are completely dissimilar.
Here's what I mean: Halogens are extremely reactive elements because they need one more electron to gain a full octet of valence electrons, whereas the noble gases are extremely unstable because they already have their full octet. As you probably already know, the octet rule states that all elements tend to react in such a way to get a filled valence shell of electrons - anything that makes this happen is favored, and anything that keeps this from happening is not.
Halogens are reactive oxidizers (they pull electrons off of other things), they're typically diatomic (having the formulaX2), they may be at any of the three states of matter at room temperature, and they basically react with almost anything.
Noble gases are, well, gases. They don't react with much, except under very unusual circumstances.