Someone else mentioned clcboats.com. I've built one of their kayaks, and I love it. All of them paddle well and they have many different types. They also have other types of boats, including a dinghy, a sharpie, and even a catamaran (technically not a cat, but a dual hull design nevertheless) that is fantastic finished.
If you build it, use luan or marine grade plywood (1/4") and fiberglass. Makes for a much prettier, lighter final boat, if you're planning on building with panels. If you're planning on doing a strip boat, the sky's the limit as for types of materials. You'll still want to glass it too for strength and integrity, but if you're careful the glass and epoxy don't add much weight.
Guillemot kayaks is also good, as is oneocean. There aren't a lot of free plans online, but most of the reputable dealers sell kits or plans and plans run from $60-$100 or so.