Frogg Toggs are the best, not expensive yet effective. Its much easier to ride in the rain when you are comfortable. The helmet thing is a bit surprising as open face can get tiring, but it does put you in the forefront of the action. Feel the wind! (and don't fall off).
Aerostich will be your friend when your wife-to-be pulls out her catalogs and starts contemplating her purchases, you will do the same. Only your stuff will be better than hers.