Evans is not highly regarded in cycling circles to be honest, - very commercial. personally i would look at the likes of Parkers international.
Agree about the weight saving but carbon fibre is a different animal interms of response, its alot less forgiving in terms of flex over rough roads or if you damage it (slipping over or banging it in the back of the car.) Alot of people, including myself stick to carbon stays and carbon forks.
Specialized are banging out some beautiful bikes this year but to be honest as long as spend the money you will get a decent bike.
Main thing to look out for is some bikes spec in campagnolo or shimano, many cyclists have a preferance, mine is shimano due to i prefere setting it up.
If you a complete amature or getting back into the game, try and have a go on as many as possible and find out what works with you best.
About the cycle to work scheme: if you are going down this route i would urge you to read the small print carefully. Having worked at halfords i know many companies actually set it up a bit cheekily as you pay back the so much each month for the allotted time but in the end you dont actually own the bike!!! Read it VERY carefully.
Dan