You've decided you want a recreational kayak, and you've even chosen what hull shape and outfitting you want your boat to have. You're 90% of the way to a great decision! Before you hand over your money, though, you'll want to consider a few final touches to make sure you're getting your perfect kayak.
Storage: Storage in kayaks comes in two main forms: hatches and tankwells. Hatches are openings into the interior of the boat, and tankwells are simply areas on the deck with rigging for gear storage. Hatch openings limit the size of the gear you can store there, and any small items should be tied in so that they don't get lost inside the boat. Remember that hatches are only water resistant--they're not truly waterproof, so anything that absolutely needs to stay dry should be in some sort of dry bag or box. Tankwells are best for large, bulky gear that doesn't need as much protection, like coolers or fishing crates. Many boats have additional tie-down points so you can run extra rope or bungee for customized storage spaces.
Consider how much storage you will need and what type-- if you're only out for a few hours at a time, all you'll need is a small day hatch for a lunch and some sunscreen. If you're planning overnighters, you'll want to look for more storage spaces, ideally hatches for more protection of vital gear.
Rod Holders: If you're not in need of a fully rigged fishing kayak, but plan on taking a rod or two along, look for flush-mount rod holders behind the seat. These are very easy, low maintenance solutions for casual kayak fishermen.
Gear Attachment: If you want ultimate freedom to rig aftermarket accessories, look for a boat with easy gear attachment points. Most modern sit on top kayaks have some type of universal track system, which makes it easy to slide rod holders and other fishing accessories on and tighten them down without drilling into your boat. Sit insides often have mounting points for manufacturer-specific accessories.
Steering and Power: Most rec kayaks don't come with rudders, pedal drives, or motors, but some are easier to retrofit than others. If you think you might want to add any of these things later, look for rudder-ready square-stern models that can easily be rigged out with steering or power solutions.