I think stick to what you are good at, if you specialise in coding then stick to it. If you have the experience and skills to do the front end design then of course offer this also....but I would not expect my website designer to design my logo or my stationery, and would specifically look to someone specialising in this area....jack of all trades master of none etc!!!
Of course you could offer these as a service but I would almost certainly have some sort of arrangement with a professional graphic/logo designer where by they give me a good price on design work I may need to outsource to them and in return you do the same for them should one of their clients want something coded, it's a win win situation should you find the right person, hence we set up this forum >
Partnerships - Graphic Design Forums: UK forums for graphic designers