Originally Posted by
xjessie007
I will be working downtown. Commuting 30 minutes is fine, I am ok with either bus or the subway. Riding a bike would be the best.

Looking form something more quiet, possibly close to parks. Is there some good place for roller-blading? (inline)
Cool.
Again, I hate to be pedantic, but there's no real 'downtown' in London. There's the City, which is the old financial/commercial centre. This area tends to centre around Bank Tube station but extends for a mile or so in each direction (bounded from the south by the river). There's Canary Wharf, which is the new financial/commercial centre. This area is way off to the southeast of the City, about two/three miles further out and only accessible by the Jubilee Line or the DLR. There's also the West End, which is the area within about a mile and a half or so of Piccadilly Circus/Leicester Square/Oxford Circus. Are you going to be working in any of these?
You may wish to consider neighbourhoods around Clapham. Whilst not the quietest in London, you have Clapham Common for rollerblading and getting to the City and the West End is relatively easy.
Rollerblading is of course done quite regularly in Hyde Park, but I've found that anytime after about 11:30 it tends to fill up with tourists. So far as I know, rollerblading is not permitted in Regent's Park. I'm leaving it open for other posters to contribute ideas, too.