||Firstly a little background to give some perspective....
I am 35, married with one daughter and a baby on the way.
I own my house. I will not reveal how much it costs! To rent a house in my part of the world is around £800 a month. You are looking at to pay at least that to rent in (a probably not very nice part of) London.
My advice would be to live out of town and commute.
I graduated with a B.Sc(Hons) in Physics from the University of Manchester in 1997.
Until about one year ago I have worked on legacy systems mostly on VMS.
I am currently working with C++ on Windows Server 2003, I am also dabbling in Realtime Java on Solaris.
I spent 2.5 years working for Logica in the defence arena and nearly 7 years at my current employer who is a global supplier of financial data and news.
I travel to work by train and my journey door to door is around 55 minutes. When the trains go wrong (which does happen!) it can take hours and hours to get home.
My salary is towards the lower end of the figures quoted in earlier post. The reason for this is:
a: My core skills are faily niche however this is changing.
b: I have been happy where I am and not moved around.
There are lots of banks, hedge funds etc. etc. in London and they generally pay pretty well.
If you are looking to get into one without experience then you will generally need an excellent degree from an excellent university. Most people in the city (apart from maybe a few HR staff at TC sponsors such as UBS and Deutsche) will not have heard of TC so it is probably worth describing TCs activities a little on your CV (resume) if you are hoping your (say) Algo or Development rating will get you a foot in the door.
If your backround is in a mathematical subject you will be preferred over those whose isn't. If you have a Ph.D in a mathematical subject you are much sought after and quant developer roles pay significantly more than 'straight' development roles.
If you have a few years experience it is a different matter and your education is less important than your skillset.
If you do get an interview then you will be tested on the technologies you claim to have experience in and will probably also be tested on data structures, algorithms and runtime performance. You will also probably be asked a few logic problems. the rest will be the usual 'tell me about yourself', 'where do you see yourself in five years time' etc. etc.
Expect a couple of telephone interviews first and then two or more on site interviews of around half a day in duration.
Many (not all) firms pay bonuses however these are not guaranteed. In the city these tend to be substantial but not as substantial as those received by traders etc.
A few things you should consider before you consider working in the city.
1: The pay is good but employers want their pound of flesh.
2: Many banks run very lean and will trim the fat whenever the going gets tough in order to reduce costs. This means job cuts.
These are just ramblings I have typed up in my lunch break. If anyone has any questions, wants to add their experiences or thinks I am posting complete bolleaux please reply to this post.