Damn, guess I'm just an exception. Online bidding sites (mostly estate auctions), 30+ tabs open. Amazon seller's page with 4 tabs open, here at AT with 13 tabs open currently, email page open along with craigslist--total of 4 tabs on that one, UPS and USPS tracking page open with 6 tabs currently, two pages for news with about a dozen tabs open between the pages, some research page open for vintage item research with about 15 tabs open......and that's right this moment.
I've had over 15 pages with well over 100 tabs open simultaneously. Doesn't matter much except after a day, FF with its memory leak can consume well over 1.2GB of memory and it sorta slows a tad, esp. if Flash use is involved.