I haven't been in London for more than 6 years by now (wow... 6 years?? really!!) so I may not have the most updated information, but whenever I was in London I always ate pretty good without distroying my budget. I always stayed in the same zone as well, I used to eat everywhere and honestly I can't remember any good ones around the immediate vicinity, but come on, from there the tube/bus connection will take you just about anywhere with ease! So... here are a few of my favourites...
(Indian) on Edgeware Rd. (not far from Paddington sta.)
(Russian) near Chalk Farm sta.
(Eclectic Vegetarian fare) also near Chalk Farm sta.
Food for Thought
Neal St. near Covent Garden
Don't overlook the pub grubs at numerous pubs everywhere, too... they usually offer great value for your money!