I am traveling to Vancouver for a business trip that begins on a Sunday afternoon in early October, and I am flying there the Friday before. I have one day - Saturday - to explore Vancouver and surrounding areas. I am considering Whistler or Victoria.
What do people suggest?

Thanks

Honestly, with one day, I suggest you stick with Vancouver. There is more than enough to do there for a day. Are you aware that it takes about four hours each way to get here to Victoria. Whistler is not that much better.
Check out Fodors destinations Vancouver and you will see that you will not be bored.

I couldn't agree more!

You could spend a month in Vancouver and still feel like you need more time!

With such a short time it is asinine to go somewhere else! (No offense) ... and icithecart is right, it takes time to get to Victoria and Whistler. That will significantly cut into your sight seeing time.

I suggest staying in Vancouver this trip. Be sure to go to South Granville for the best art galleries, best restaurants, best clothes shopping, best home decor shopping, (highlights are Douglas Reynolds Gallery, Uno Langmann, Ian Tan Gallery, Panache Antiques, Guild House Antiques, 18 Karat, Atkinson's, Chachkas, Farmhouse Collections, Meinhardt's, West Restaurant, Red Door, Ouisi Bistro, Bin 942 Restaurant, Cookworks, Rocky Mountain Soap Company, plus more) www.southgranville.org. See Granville Island for some great West Coast laid-back culture; good food, fun and eclectic gift shopping, www.granvilleisland.com. Arts Club Theatre for a good play or two, www.artsclub.com. Great nightlife at Canvas Lounge, www.canvaslounge.ca. Ride a rental bike around the Stanley Park seawall, http://vancouver.ca/parks/parks/stanley/index.htm. See this website for more about Vancouver in general, http://vancouver.ca/visitors.htm.

I agree with the others - stay in Vancouver! Rent a bike and bike around the seawall/Stanley Park. Take the ferry (or bike over the bridge) to Granville Island. Visit the cute restaurants/shops around Gastown. Walk along the water from the marina at the end of Stanley Park up to Canada Place.

We were there for 2 days before our cruise this summer, and wished we had more time there.

We spent 4 days in Vancouver in July and that wasn't enough. My favorite day was spent walking along English Bay and then around the seawall of Stanley Park. Biking that area would be great, too.

Thank you all for your advice.