Well for me Rainham has to get a vote, being my local. Not the most attractive place in the birding world im sure being a semi rural site.
Views consist of the Eurostar track to France, Rubbish Dump, Part of the Thames Barrier, Dartford QE2 River Crossing an old power station, the Canary Wharf Building and associated Towers in Docklands, Haulage Tanker Storage Yards, the old stone barges, Purfleet docks, numerous Pylons and i almost forgot all the rubish that litters the other side of the Thames wall as you walk along it.
That said, get into the main reserve and somehow that all seems to vanish; its still there obviuolsy and in sight but you dont seem to mind.
The pylons and power stations are our roosting / nesting / observing places for the resident Perigrins, who will dive onto prey in the marsh pools in front of you scattering upto (last count) 1100 wigeon, 1000 lapwing, 1000 teal, 500 golden plover and many others into a mass flight.
The Rubish Tip is part of why we go, i have actually been to the marshes, not viewed the marshes but stood on the roadside watching Gulls in the tip for 5 hours. CRAZY you may ask well not really, i managed to be one of about 40 birders who got to glimps the UK's first sighting of a Slaty Backed Gull the other week. (
Birding etc with Dominic Mitchell for more on that). Caspian, Yellow Legged, LBB, GBB, Herring, Common & BHG all easily viewable with upto 10000 gulls visiting (see the vids on that site i just linked).
The rubish along the Thames helps us with more gulls and the Thames it self gets numerous species, Eiders, Great Egrets, Gannets & Bitterns to name a few.
The woodland area provides the usual suspects and on average up to 70 Ring Necked Parakeets.
I could go on, January the first saw 96 species recorded on one day, its life list is now over 205.
Well worth a visit.
Sorry had to add a shout for the Essex
