It is impossible to say which wetsuit is the best. Why? Because even if the wetsuit gets the "Wetsuit of the year" award this doesn't mean that this is the best wetsuit FOR YOU! When you are choosing a cold water wetsuit there are a few thing to consider. If you want the best of the best then your cold water wetsuit should have:

• Liquid taped, liquid sealed... seams. There are a few names that wetsuit manufacturers use for this but the point is that they seal the wetsuits seams using liquid rubber and this will make the seams waterproof. If you want a good winter wetsuit then this is a must.
• Blindstitch, double blindstitch. This is the type of stitching usually used in winter wetsuits. The catch is that with blindstitching the needle never completely pierces the neoprene so in theory there are no holes that go all the way throug and no holes for the water to come in. Double blindstitch is the same thing but from both sides of neoprene. This makes the seams much stronger but some of the holes can connect all the way through so you need liquid taped seams.
• Elastic, stretchy neoprene. Your wetsuit will be easier to put on and take of. It will fit you better and there will be less room for cold water and since cold water wetsuits are thick stretchy neoprene will put less strain on your arms when you are paddling. More flexibility the better!
• Zipper. Shorter zipper and/or special shape of the teeth on the zipper means less water can get into your wetsuit through the zipper. And if it still comes in? Then you need...
• Batflap, batwing, watershield, water barrier... again, more names for the same thing - a thin layer of neoprene on your back under your zipper that is thin and elastic enough so it doesn't get in the way when you are puting on your wetsuit but it stops the water from entering into your wetsuit through the zipper and diverts it back out through the hole at the bottom of the zipper.
• Internal insulation, hollow fibers, aerocore, airlite. This is a special material made mostly out of hollow air filled fibers that has great insulation capabilities. Good wetsuits are lined with this material on the inside.
• Silicon on wrists and ankles. If you put silicone or some other rubbery material on the inside of the wetsuits wrists and ankles the wetsuit will stick better to your skin, it won't slide up and less water will come inside through those holes.You do not want this on your collar since it will give you a bad case of wetsuit rash.

This is mostly it. Now comes one of the most important parts - the fit! Wetsuit needs to fit you well, to be snug... even if you buy the best wetsuit - if it doesn't fit you - you are just wasting your money. Different wetsuit brands have different wetsuit models and some can be more suited for your body shape than others. This is why it is imposible to say this is the best cold water wetsuit. It can be technologywise, but if doesn't fit you, try another model.

Generally, if you want the best cold water wetsuit stick to big brands like Billabong, XCell, O'Neill, Rip Curl, Body Glove. If you choose their top model you can't miss.