Helmet, go with what fits. Get one that will fit to your head. I can't wear ARAI helmets, the are too awkward, SHOEI helmets fit me the best, but like the ARAI's, are costly. Go to the local bike shop and try some on, see what fits.
Jackets, again, go with what fits. Joe Rocket has some good stuff, just a matter of what you want to. If you want to save a little on the jacket, find one you like at the local shop, then check newenough.com. They have new and "slightly used" gear that can save you money in the long run.
Colors, what ever floats your boat. Black generally goes with anything. If you sell your bike, and get a green bike, you won't have to buy a green jacket.
Good luck, welcome to the site. And you are on the right track with getting and wearing your gear. Suit up, even if you running to the store a 1/4 mile away.