Depends what you are wanting really. I have found that with commuting every day all waterproofs eventually loose their water proof...ness. I have shelled out for expensive stuff but even that will leak after a few months of winter riding. Also I find that the salty/dirty/gritty water spray off the motorway kills the jackets and makes them look rather used in no time so expensive gear, for me, isn't really worth it.
I now use over jacket and trousers. I found the one piece suits (I had 2 before switching to two piece) to be a bit unwieldy especially when arriving at work, hanging it to dry out is not as easy as 2 pieces etc Another bonus is that your actual riding gear stays as clean as a whistle underneath.
I have also found that even waterproof over gear leaks eventually. A fresh set will keep you dray in the heaviest of rain, for a few weeks. I find that the crotch will leak first, then on the jacket the front shoulders. Visually there isn't anything to let water in but they all do. I have had a few sets over the years, Alpinestars, Armr, RST etc I am currently using Richa (jacket £30, Trousers £20) and they are probably about the best I have used. I did resort to putting some black instant gasket on the seams of the crotch and it did indeed sort the problem....for a few weeks
They pack down very small (I stash mine under the seat if I am not using the top box) and can be easily washed etc easy to wriggle out of at work and whatnot.
I have seen people get good results with sprays and nikwax and it does work for a day or two.
I believe a lot of people rate the Rukka gear, which is expensive. For me though, I find over jackets/trousers etc the best solution, they work, are cheap, keep my normal gear clean, easy to store plus you don't need to factor waterproofing into your gear purchases.