There are dozens of good manufacturers and hundreds of models. Since you are so unfamiliar with them I strongly recommend two things: first, rent or (better yet) pay to go on a guided paddling outing with a reputable outfitter. Almost every region of the country has kayaking dealers and outfitters nowadays. And second, let a qualified outfitter help you fit and select a boat for your needs. Your physical size, athletic ability and the kind of places you intend to paddle are very important in getting the right gear. Also your budget. Even for just fishing and quiet paddling you need some basic instruction in how to paddle (most people do it wrong and it becomes tiring and can lead to injuries) and you should have some basic safety instructions and drills. Most flatwater and fishing kayaks are very stable, but it is always possible that you can be tossed out of any boat by a large wave or boat wake, so you need to know and practice how to be safe. This is critically important if you intend to go out on a big lake, like Lake George in NY or any of the Great Lakes. Most cheap recreational style boats are not safe for those conditions.
Many people are tempted to buy a cheap kayak at a regular sporting goods or discount store but this is not really the best way to do it. Try to find a good independent outfitter (they usually sell backpacking gear or climbing gear in addition to kayaks) or go to an L.L. Bean or REI outdoor gear chain store where they will have salespeople trained and qualified to outfit you right.
Meanwhile, read up on kayaking and gear selection on this site:
http://www.paddling.net
It is a free paddlers' site that can tell you much of what you need to know about the wide range of kayaks and their usage.