Hi Chadwyck,
This topic of course pops up quite a bit from time to time! and there's lots of opinions and thumbs up from everyone who've lived in these areas etc.
The 'hoods' you mention are all easily liveable and some more than others depend on how deep and fat your wallet is. I say definitley find out more about each place - can't beleive the person you spoke to has not recommended Ealing! - yes there are 'some' dodgy areas like any other, but Ealing is still a very very desirable place to live overall.
I suggest you do expand your search to other areas as well, these are just a few, and there are alot of others which you can consider. Driving and commuting into these areas is certainly possible, but you will pretty much experience alot of delays and jams, and if something goes wrong (accident, roadworks etc) you'll really pull your hair out. Consider some of the areas around NW London as well, Pinner, Harrow, Rickmansworth, Watford, Hatch End, Stanmore, Ruislip etc etc. I understand these places are sort of 'out of London' as it were - but practically and financially do make good sense to consider. When I worked in Ealing (just off the Gyratory) people used to think I lived in outer Mongolia for commuting from Slough everyday - which always made me laugh, although not having to live on my own, the difference in monthly rents was nothing to be sniffed at for living 'so far away' - not saying you should come out this way (although it's still a possibility, especially when you see places in Gerrards Cross, the Chalfonts, Beaconsfield etc!)- but I do urge you to consider a little further out seeing as you've placed a substantial importance to commuting. As it's Marlow, then I definitley recommend doing the commute by driving, else you will (I think) need to change quite a few trains and simply would take you a good hour at least in increased times. Also, consider some areas of North London, Kingsbury, Hendon, Finchley, kinda areas.
I'd also put forward the idea of getting a decent Diesel engined car as it'll have plenty of time to warm to operating temperature on your commute and thus giving you the best MPG performance.
Any other questions or queries just let me know and I'll do me best to help!
Cheers! DtM! West London & Slough UK!