First thing I would ask is whether the hour and a half is actually realistic.
I used to commmute, but decided I didn't want to waste such a large proportion of the day travelling with small children so gave it up and now work for myself from home.
My DH still commutes. Technically his commute should be just over an hour. Trains from here are supposedly 45 minutes then a couple of stops on the tube and a short walk.
However once you factor in trains being late and/or problems with the tubes, more often than not with one thing or another, it's more like an hour and a half.
I loved working in London but for me personally, with a big commute, it would have been a long day away from DCs and I wouldn't do it now.
I also agree when you say 'not more money', are you factoring in what will probably be astronomical travel costs? I think my DHs is about £5000 a year for just the train iirc. If you are travelling by car have you factored in petrol/parking?
I do agree with a lot of Heroine's plus points though, my view is just that I wouldn't do that now I have DC. DH doesn't see our boys more than once or twice during the week for about 10 minutes if they wake early enough in the morning. He leaves at about 7.15 and is back around 8.30.
Is it the kind of job where you can literally work 9-5 and be out the door by 5.01? Because if so, you could in theory be home by 6.30 or not far off, which wouldn't be so horrendous.