I would like to know, in your opinion, which broker do you prefer for trading currencies and/or stocks and options. The reliable, low commissions would be some of the criteria I am looking for. Also, could you tell me a popular online forum about forex, stocks and options.

regards

Here these sites should help you with your research:

http://www.forexbrokerguide.com/forex-broker-search/search-results/?criteria=1&jr_country=United+Kingdom+%28UK%29&order=featured&query=any
http://www.fxcm.co.uk/
http://www.ukcitymedia.co.uk/stockbrokers/currencies.php