As Dana suggested, the 7 weight will probably serve you well. The 7 is a good all around rod. The most popular length is 9 ft, although I prefer the 9'6" or 10 footers.
I do suggest that you go to your local fly shops and test cast several.. Find the one YOU like best. The rod I like may not be the rod that suits you. IE I prefer the fast action rods, you may hate them.
Fisrt decide the price range you are going to look at. Then try the rods in that price range.