Having had HP printers for ages now (I have always found them to be the best) it's easy to forget the quality of their ink cartridges. They never blob or run , or worse leak. Contrary to the negative reviews I managed to read the instructions for the printer and realised you had 5 ink cartridges with 2 blacks - Photo black and plain black so I've never had an issue ordering the correct item. In fact the HP solution centre software helpfully tells you exactly what you need as well and the ink monitor tells you yet again which is the correct cartridge.
Amazon usually have the cheapest cartridges though it does pay to look to make sure.