Cameras, by a comfortable margin.
See: Average IP Camera Costs
The average camera cost is definitely coming down but in almost any given system, the cost of the camera is more than the recorder. On the very low end, you might buy an 8 channel recorder for $200 (or $25 each) but the cameras are still usually $50 - $100 each. On the high end, you might spend $200 per channel for VMS software plus $100 - $200 in hardware but the cameras in those systems usually average $500 - $100 each (including higher end fixed cameras, multi-imagers and PTZs).
"Recorder" is too generic of a category, IMO.
Do you mean a cheap NVR? $500 will get you a Hik 8-Port NVR and a 2TB WD Purple drive, putting the cost a little over $60/channel. While you can get a camera for $60, from a practical perspective you'd probably spend $100+ per camera right now. In this scenario, the recorder is going to be much cheaper than the camera.
If by recoder you mean a VMS appliance with a more full-featured client component, you're around $300/channel for an 8 Port/2TB unit. Although in that category you might spend more than $300 on the camera as well, or at least some of them. So then your average camera price might be roughly on par with the recorder price per channel.
However if by "recorder" you mean a full VMS platform like Avigilon, Genetec, Milestone, etc. then you could spend as much as $2000 (250 per channel) for an 8 channel license pack, and that doesn't include the hardware to run it on. Hardware could be another $1800-$4000+, driving the per channel cost up to $500-$600+ easily. Here too you might end up using higher priced cameras in the $500-$1000 price range.
For the latter 2 categories you'd also have to take ongoing support fees (if any) into mind. Over a 5 year lifespan you could end up paying another $50-$100 channel for support with some vendors.
All things considered, I'd say the two costs are roughly equal today. In the low-end category the recorder might be as much as 50% less than the camera cost per channel, but you're talking about such low dollars that they come out to be roughly equal ina sense. In the mid range they're probably within 5-10% of each other, and on the high end you might expect the cameras to be about 20% higher overall.
Not discussed is also installation labor and setup. A cable drop can easily be $200 per run, plus some technician time for setup. From a budget perspective you could probably start with something like 33% for recorder, 33% for cameras and 33% for installation/setup. I'd be curious to hear from some integrators if that is about right.