Hi there,
I visit Singapore quite frequently and can recommend you some nice locations with always surprises, even if I am not resident birdwatcher.
First is Sungei Buloh, for waders, raptors and special birds (e.g. Storks frequently seen there).
Second is Bukit Timah, for forest birds (very hard to see...).
Third is Botanic Gardens, the lake and the forest close to the Ginger Garden, probably the best places.
Let me know if any question
Here is a summary birdlist on my latest trip (not extensive...):
2010.11.13 Ashy Minivet Sungei Buloh
2010.11.13 Arctic Warbler Sungei Buloh
2010.11.13 Crimson Sunbird Sungei Buloh, Botanic Gardens
2010.11.13 Brown-throated Sunbird Sungei Buloh
2010.11.13 Common Tailorbird Sungei Buloh
2010.11.13 Pied Fantail Sungei Buloh
2010.11.13 Olive-winged Bulbul Sungei Buloh
2010.11.12 Stork-billed Kingfisher Bukit Timah, Botanic Gardens
2010.11.11 Straw-headed Bulbul Bukit Timah
2010.11.10 Ferruginous Flycatcher Botanic Gardens
2010.11.11 Large-billed Crow Bukit Batok
2010.11.11 Yellow-vented Bulbul Bukit Batok
2010.11.11 Banded Woodpecker Bukit Timah
2010.11.11 Common Goldenback Bukit Timah
2010.11.11 Western Osprey Bukit Timah
2010.11.11 Grey-headed Fish Eagle Bukit Batok
2010.11.11 Blue-throated Bee-eater Bukit Timah
2010.11.11 White-crested Laughingthrush Bukit Batok, Bukit Timah
2010.11.13 Yellow-vented Bulbul Sungei Buloh (actually everywhere)
2010.11.13 Asian Koel Sungei Buloh, Botanic Gardens
2010.11.13 Dollarbird Sungei Buloh
2010.11.13 Zebra Dove Sungei Buloh
2010.11.13 Spotted Dove Sungei Buloh, Botanic Gardens
2010.11.13 Pink-necked Green Pigeon Sungei Buloh, Botanic Gardens
2010.11.13 Emerald Dove Sungei Buloh
2010.11.13 Ashy Tailorbird Sungei Buloh
2010.11.13 Lesser Sand Plover Sungei Buloh
2010.11.13 Pacific Golden Plover Sungei Buloh
2010.11.13 Oriental Pied Hornbill Sungei Buloh
2010.11.13 Striated Heron Sungei Buloh
2010.11.13 Purple Heron Sungei Buloh
2010.11.13 Little Egret Sungei Buloh
2010.11.13 Grey Heron Sungei Buloh
2010.11.13 Great Egret Sungei Buloh
2010.11.13 Black-crowned Night Heron Sungei Buloh
2010.11.12 White-throated Kingfisher Bukit Batok
2010.11.13 Common Kingfisher Sungei Buloh, Botanic Gardens
2010.11.13 Collared Kingfisher Sungei Buloh
2010.11.13 Black-capped Kingfisher Sungei Buloh
2010.11.13 Common Iora Sungei Buloh
2010.11.13 Black Baza Sungei Buloh
2010.11.13 White-bellied Sea-Eagle Sungei Buloh