The Swisshotel is very close to Raffles but I haven't stayed - closer to the Esplanade etc but further from Arab St - all walkable or very cheap taxis if it's hot and you're travelling with children. Raffles will be much nicer of course - I haven't stayed since the refurb quite a few years ago. The other hotel I like is the RC - the marina area is quite nice but you'd need to use public transport or taxis more. Also liked the Shangri - la but not so keen on the location as the only places nearby and walkable are Orchard Rd (shopping malls - not that interesting as same brands as at home and no cheaper) and the botanic gardens.