I recently bought a body glove epic II membrane dry suit. I have used it quite a lot. Its great... no leakage, good valves, zip cover, braces, etc. I would recomend it to anyone. It is fairly expensive but not overly for a suit of its quality. I managed to get an undersuit thrown in for £500 (not sure if that means anything to you). Initially its a lot of money but a good suit will last for years without problems (so long as you look after it). I was diving in 1 degree C water today and was perfectly comfortable.
At the end of the day, how much you're willing to pay is your decision but bear in mind a cheap one will probably not last so long.
Hope this helps.
Trewbs