My girlfriend lives in Toronto - here's what she says:
Head down Queens Street (for shops - The Eaton centre is there as mentioned above) past Nathan Phillips Sq (where you can ice skate or see fountains) and there's some really nice restuarants there and expensive shops. You can visit Chinatown if you go up Spadina from Queens Street.
You can take a tram/street car down College to Kensington Market - fun to explore there. Toronto Uni campus, near Hyde Park is nice to see.
Bay Street is the expensive street with all the shops like Gucci and Prada and it's fun to window shop. There's also a cheap Winners (dept store) at the end of the street right by the ROM (Royal Ontario Museum).
If you want to go clubbing, you can go to Peters Street, Richmond or Adelaide. Menage and Mink are the first clubs that come to mind as good ones.
The Ontario Science Center is probably a bit out of your way if you are staying downtown but it's worth going to see one of the huge IMAX 3-D movies there. Also the up Yonge street from Bay until Eglinton you will find many shops and good pubs. Also down Eglinton, east of Yonge is a good pub area.
If you're into visiting huge malls, Yorkdale, Eatons Center and Scarborough Town Center are the biggest 3.
Sorry if this is a bit of a messy post - I was trying to type as fast as she was talking - not an easy task I can tell ya!
Hope this helps.
Edit: at the moment its $23 CDN per £10 - she isn't a happy bunny with our exchange rates at the moment
