Hi JC , you ma go to clrak quay and boat quay which are along singapore river , there are lots of interesting pubs and restaurant over here.
Singapore river is a small river with historical inportance in Singapore, there's also lots of uniqe shop to explore along these areas.
The nearest MRT station to clark quay and boat quey are clark quay station and raffles place station respectively.
And you may also go to china town , little india or arab street that are able to explore diffrent culture and have a diffrent shopping experience.
Bugis street that Justin recommend is another place great for shopping too, singapore's youngster have always love to spent their weekend too.
There' s a bugis villige opposite this bugis MRT station that sell cheap and nice fashion apperels .
And of course orchard road are more for the branding shopping.
Understand that you would also like to explore on locl art and music,
you can head for this
esplanade which is a new landmark in singapore, it's a art and music center in singapore ,
it held diffrent kind of and concert regularly -
http://www.esplanade.com/index.jsp
You can browse through their events from their website,
And for musuems , you can get to know more from this website that have some recommendation
http://singaporefive.com/
To be frank , I have never been to any of these musuems yet , my sense of art is really week , heh heh,
Ok , I think thats all I have for you temporary till I can think more later maybe.
Hope all these info will be able to be useful for you. ,
Just let us know anytime if you need more info.
Cheers