London, UK Members: Moving there from US (SoCal). What to know

[notoriousbee]

Wussup Guys! I'm brand new to the site and was recommended here through another forum. I currently live in southern California and am in the online advertising space. My current employer has reached out to me about a potential opportunity to relocate to our EU headquarters in London. I know next to nothing about living in the UK. I have traveled there in Sept of 2010 for work and was there for about 10 days. At the time, I was just taking it all in and being a tourist pretty much. I wanted to ask you guys a couple questions about moving/living in the UK.

To set the landscape, here are some details:
- current US income ~ $55-65k
- currently renting 3br apt ~ $1k/mo (my share w/ utilities)
- no real debt outside of credit cards
- I'm single, late 20s
- grew up in Chicago, prefer big city life over suburban life
- move likely to happen April 2013

Company details:
- will be providing moving expenses
- will be living there between 2-4 years
- anticipated salary will be 25% higher (in pounds) based on cost of living (est. 48,000 pounds)
- office is located in Central Saint Giles. I remember it being around 3 blocks away from the British Museum.

Here are some of my questions:

1. Ideally I'd like to live within a 30-40 minute commute to work. What amount should I expect to pay for a decent 1br apt? How big are they? 400 sq ft.? 600? 800?

2. Considering the location of my office, what areas should I consider looking for an apt?

3. What utilities do you have to pay for? Electricity, Gas, Trash, Cable/TV, etc.?

3. How much do you have in pay in taxes (US ~ 25%)?

4. What is a comfortable salary to earn living as a single male in the UK? 35,000 pounds? 50,000? 80,000? My salary is negotiable.

5. How much would I likely be spending on a Tube fair per month/year?

Any feedback and suggestions are greatly appreciated!