There are many tennis stores that would allow you to demo racquets. Also, if you have a close friend, you can ask if you can exchange racquets for a day or two. This is how I changed my old racquet to the Babolat Pure Drive.
basketball..i would get nike. adidas is more like soccer. but if youre a true adidas fan, get that, like me =] best backpack--jansport bags--nike or adidas. i would pick adidas shoes--nike jackets--adidas ohh. and never wear mix and match your nike a...
you should buy a bag based on the number of racquets you have (or will potentially have) and extra gear you haul around. wristbands, headbands, rosin bag, dampeners, overwraps, cell phone, etc. I wouldn't recommend a 6 racquet bag for only 1 racquet....