I used to say Fleet Pond but two things now mitigate against that: first of all it has been spoilt with dredging spoil being built into islands that now obscure the view as well as removing what used to be a large expanse of open water and holding big numbers of screeching Black-headed Gulls; secondly the whole place is now more country park than nature reserve and far too busy to be fun.
Fortunately many years ago I undertook a challenge against James Andrewes of this parish to see who could record more birds within an arbitrarily chosen radius of 10 miles from home, and I now consider that my local patch. Fleet Pond is still in it but I have other choices of which the best known are probably Frensham Ponds and Common, Thursley/Ockley/Hankley Commons, Tices Meadow (though I rarely go there as the big list of good birds is marred by the inability to get good views without the Hubble telescope) and Moor Green.
The full reach is from Bracknell in the North to Frensham in the South, from Greywell on the chalk in the West to Sunningdale in the East. Hunting around in the gaps between the known hot spots is always interesting, though some haven't justified more than a couple of exploratory visits!
I couldn't tell you the full list but during the challenges - we ran it for two years - I got into the 160s both times, and one was 1993 when I found a spring Citrine Wagtail at Fleet Pond. Good regular birds include Great Grey Shrike, Woodlark, Firecrest, Bittern, Little Egret (one went past my window this morning) Peregrine, Jack Snipe and Osprey, not to mention the fabulous and increasingly heroic multi-year returning Colin the Cuckoo.
Occasionals and rarities have included Pectoral Sandpiper, Black-winged Stilt, Red-footed Falcon, the aforementioned Citrine Wag, Ring-necked Duck, Ferruginous Duck, Great White Egret and both White-tailed Eagle and White Stork before the present vanity projects got going. Merlins, Hen Harriers and Short-eared Owls occasionally stop off or over-winter though their location is unpredictable for the most part.
For an inland patch its pretty good!
John