Check for balanced parentheses
Aside from stylistic concerns (as a Java/Clojure guy, I'll let you C#'ers decide on that stuff), I don't see how this a correct algorithm, unless additional constraints are given in the problem statement. Consider this input:

([] ())

Now, clearly that is balanced. And if you reverse it, you get:

))( ][(

But if you compare this reversed input with the original input, you don't find that each open bracket matches up with its closing bracket in the reversed string: the first character and the last are fine, but the inner pairs don't balance at all!

So, unless you are given the further guarantee that the input consists of N opening brackets followed by N closing brackets (ie, no opens after the first close), you can't just compare the reversed string.