Hi all, thanks for your inputs! They've been very helpful and informative. I've been to several bike shops today and yesterday, and today one of the bike mechanics in one of my LBS suggested I consider touring bikes? He told me these are essentially road bikes, but have more relaxed geometry so would be more comfortable and less prone to back pain especially on long rides and have stuff like enough clearance for mudguards, space for rack, more spokes on the wheel etc that make it more versatile that can basically "do it all" including some light offroad which it handles it a lot better than pure road bikes, while being faster and lighter than CX bikes.
Though I love road bikes, I have been warned by many of my cycling friends that they're very fragile and components start breaking easily especially if you ride it all year long in all weather conditions including dirty roads, some light trail/gravel etc. The mud would kill it. One of my friends just paid 200 quid to service his trek 1.1. apparently...
As for CX bikes they seem to be rather slow and heavy. I tried the Specialized Tricross today. Though it looks like a road bike it is actually heavier(!!) than my hybrid by 3 pounds, and the thick 32mm tyres with lots of tread looks quite slow to me.
So the shopkeeper suggested touring bikes which seem like the best compromise! Almost as fast as a road bike, and more comfortable, light and can handle more abuse and offroad conditions than a pure road bike. He suggested me this model, initially 800 pounds but I can get last year's model for 600:
http://www.evanscycles.com/products/ridgeback/radium-2012-road-bike-ec032067
another option is the Ridgeback Voyage.
What does everyone think about touring bikes? Would these be a good one to go for? Road bike speed + terrain versatility.