I used to think that I had to spend good money on wet weather gear to stay try. Turns out you don't have to.
After racking up thousands of kilometers riding in the rain - sometimes fo 8+ hours a day in the absolute pissing rain, I can safely say that there are options that will keep you try.
Work supplies us with our leathers and our "fisherman style" wet weather gear. You know the stuff, looks kind of like this:

The leathers go underneath and the XL PVC wet weather jacket and pants go over the top. If it's a really cold day AND raining I'll wear: thermals, shirt, polar fleece jumper, leather jacket then the PVC gear. Keeps me warm and dry. If I fall off, I'm not too concerned about the lack of protection from the PVC stuff because I have my leathers on underneath.
The jackets we are supplied have neoprene inserts in the ends of the sleeve, to soak up and rain that might get through, and a velcro fastener to fasten the sleeve around the outside of the glove and the wrist. The pants have the same velcro strap at the bottom of the leg to tighten them around your boots.
No other jacket I've owned has worked as well.