It depends on how social you are I assume. As we are on the subject of your sexual orientation, my male gay friends wear me out who live in Zurich. It reminds me of the all you can eat Chinese buffets back in Michigan. While I can find something to do, every day of the week in Zurich, apparently there is a party everyday of the scene in those social circles.
I haven't been to Basel as much as I have been to Zurich. But, there does seem to be a lot of charm in the slowness of the town. You will never see that many people on vintage bikes in Zurich as you do in Basel. And it does seem like they take more advantage of the open river fronts, then the evening beer can by the lake tradition, Miller time, on Zurisee.
I prefer Zurich to Basel, but I don't dislike Basel. Like Adrian said, it is on the doorstep of France and Germany, and very close to a very cheap low budget airport that can have you in 45 minutes in Cannes, for less then 100CHF, booked in advance. The French are a bit of a homophobe culture. Although I do believe it is great deal the kind of homophobia that the biggest sounding bigots are the mostly likely gay themselves.
But if you work in Basel, trains are direct into HB, and the GA is wonderful. You can go anywhere, anytime in CH with it. And also allows you to have discounts on the trains in Germany and Austria as well. I mean to insure an old car will cost about 7 o 800 CHF a year, parking from 50 to 150 per month, strassenverkrersampt 350 or so, impossible to not get a speeding ticket or two here so 300, parking fees daily 5(atleast), and not including gas, winter tyres, accidents, or other maintenance to your car(oil changes, windshield wipers etc), 3500 for a year in transport, it's not a bad deal at all. And if you decide to stop using it mid way, they refund you the difference.
I knew of a girl that worked in San Gottardo, and did a daily commute from Zurich to there and back. She was single, and from another country, and said she wouldn't have it any other way. If you choose Zurich, introduce yourself when you get here. There are plenty of friendly folks willing to have a beer...or whatever is your beverage of choice.