If you have a day, the Sea-to-Sky - Duffy Lake - Fraser Canyon circle trip is awesome! Head up to Whistler, on to Pemberton, through to Lillooet, over to Cache Creek, and back down the Canyon to Hope... or in the reverse direction, if you prefer. Lots of amazing views, varied conditions - from open freeway to narrow winding second-gear stuff - and it brings you right back where you started from.
http://maps.google.com/maps?f=d&sadd...62&ie=UTF8&z=7
Edit: ah, I see someone's already posted this loop... but instead of going Lillooet-Lytton, go across to Cache Creek through Marble Canyon. The stretch back down the Thompson River from CC to Lytton is some great driving, too - you go from two wide, fast lanes, around a bend, into a super narrow, winding stretch hugging the cliffs.