Ok, I'm going to give ya the quick run down before I'm off to work.
As of right now, there are 5 London teams in the EPL. That may change next season, depending on who gets relegated/promoted to/from the lower league.
Chelsea, Arsenal, and Tottenham are the "big three" in London. All really good, all have a spot of going to the Champions Leaguse (Which pits the best teams in Europe against each other) next year.
Fulham's a mid-table team. But I like them because they have Clint Dempsey, (in my opinion) the best current American player. From Texas!
Q.P.R just got promoted this season, and may or may not get relegated again by the end. I, honestly, don't know much about them.
Of course, there are other teams in the lower leagues that are always worth a watch. West Ham comes to mind, simply for their historical importance.
As for picking a team, just look up vids from the current season, read up on them, and see which team bests suits "you."
Although if you pick Chelsea I will relentlessly make fun of you, as last year Chelsea paid Liverpool 50 million pounds for a striker who has scored a hilarious total of 5 goals this season.
And BAM. I'm done.