One thing that is very convenient for a single-handing sailor, especially in crowded harbor situation where short tacking may be necessary, is a self-tacking jib. Most boats don't have this, but can be retrofitted with it fairly easily.
There are pros and cons to leading the lines aft to the cockpit or leaving them at the mast. Singlehanding, having the lines lead aft, provided the winches are large enough to compensate for the additional friction in the system, is probably a better choice.
A windlass and a good primary anchor are key to single-handing if you're cruising. Having a badly designed anchor that requires it be raised and reset is a losing proposition when singlehanding a boat. Makes for an uneasy night on the hook too.
I can't emphasize how important the safety harness, jacklines and tether are to the singlehander. You have to stay on the boat
An autopilot is a very good idea... one of my friend's has defined hell as a long voyage, singlehanded without any form of selfsteering.
Lazy jacks or some other system of containing the mainsail when dousing it are a must. I would also agree that in-mast or in-boom furling really has no place on a boat for a singlehanded sailor.
A roller furling headsail is a good thing... but having something like the ATN GaleSail is probably wise, for when the weather gets really bad.
I'd also agree that a tiller, especially on a smaller boat, say less than 35', would make far better sense than a wheel. Rigging a line to hold a tiller in position or using lines to create self-steering is much simpler with a tiller. You can also steer a tiller without using your hands to some degree. A tiller also gives you more feedback and that can help you know if the boat is overpowered or badly trimmed.