Hi all, newbie here from London, thanks for reading

I'm stuck in the (long and painful) process of trying to buy a new bike. I've been researching and test riding for months and I just can't seem to find the perfect one that is the right balance of price, weight, fit, and looks nice too! I know all the staff in my local bike shop by name and I think they think I am a bit tedious now! So any help and advice you can give me would be much appreciated!

I'm looking for a hybrid / flat bar road bike, mostly for commuting and quick trips to the supermarket but also for fun bike rides and exercise when the weather is nice. My old bike (which was stolen) was a steel ladies step-through, incredibly heavy, and a real effort to ride. So I'm looking for something light, but which can carry a bit of shopping, and will handle the bumps on London's roads. My budget is GBP £500.

I've been looking at the Trek FX range. The 7.2 FX fits comfortably within my budget and the 2014 model is pretty! But it feels quite heavy when compared to the 7.3, and it's much slower off the mark at traffic lights. The 7.3 is £100 more expensive (and therefore over budget) and I'm not a huge fan of the colour. But is it worth paying a bit more and putting up with the look because it's lighter? It has an aluminium fork while the 7.2 has a steel one - but I've read elsewhere that some people don't rate an aluminium fork much and say a steel one is better for ride quality even if it makes the bike a bit heavier.

Also how do you know if you need a WSD model or not?

Alternatively, can you suggest any other brands I should look at? If it helps inform you, I'm 34, pretty fit, do a lot of indoor spinning classes and running, so a sporty bike would suit me. My current commute would be about 5-6 miles each way. I live in London and it's winter, so I'm likely to be cycling in the dark, cold, and rain...

Your thoughts and advice about how to get out of the spiral of confusion I'm in would be much appreciated!