wats ur budget?
the most famous one is probably the Tung Lok Linzhi Restaurant.
Find them in Far East Square and at Liat Towers.
there is another one at Chinatown called Lu Qing Qing (green green
green), with a branch in Joo Chiat. Quite nice. They used to have
very nice la-mian, now the shi-fu gone liao, so no more la-mian...
pity.
for kopitiam style, try the one at upper Serangoon Road, opposite
Church of the Nativity of the Blessed Virgin Mary Blk 356. The
whole kopitiam only serves vegetarian and drinks. good and
economical.