I have been living in Isleworth (Hounslow) in West London since 1993 and have found it very nice area. Tube station is there to get to central London within about 35 min. Heathrow airport is almost around the corner. Rental situation is not bad. The only problem (for few) could be that it is mainly Asian majority area. But wihin a one mile or so you would have Mixed race areas or even White majority. Safety wise is fine as I have never had any bad experiences or never heard of many.
But I am sure Chris would be here soon to give you countless number of choices.
VHGuy is right - If you were travelling from the outer bits side to side say North to South would take you well over an hour and at the least two changes on the tube and not all of London is well served by the Tube.
Say where you are working - then we can work it out - Maybe :-)
Feltham is West of London and connects to Waterloo by overground rail. Not far from Hatton Cross on Piccadilly Line. Reasonably safe and rents reasonable. Shopping greatly improved here too.