I've tried felt tips, fountain pens, fibre tips, and just plain pencil, and just using PS to digital outline in black.
Felt tips I find run too much and soak into the paper when you try to outline, or the colour isn't dark enough to get a black line without bleeding over the pencil edge.
Fountain pens are decent but hard to find in small sizes outside the calligraphy sets, and they're expensive, plus the ink is difficult to find since it's a speciality item now. I've found probably one retail store that sells calligraphy fountain pens with the fat square nibs, and the thin sharp nibs for detailed work. Costs a lot for a handful of pens, and even more for the thinner nibs. So I invested in a couple fine-nib dipping ink pens that use india ink, unfortunately the nibs each can be fairly expensive dependant on the type, and retail stores don't really carry them unless its a speciality art-supply store. You could be looking forever for a local supplier, so the Net might be your only option.
The cheapest pens and more readily available ones are the fibre-tip nibs that re a dime a dozen for the 0.07mm to the 0.02 mm nib sizes. Easy to use, but won't neccessarily come in permanent ink. Most of the time they're water resistant but not water-proof. You get them wet they run like mascara. Sharpies are good but I find that even their thinnest and finnest nibs are too fat for fine detailed work if I'm inking a pencil sketch, cheap as chips from a good stationary store but a pain in the neck to use when they bleed over the line like a felt-tip pen, yeah they're waterproof but if you screw up you can't just erase the ink. Fabercastell's are better but the ink wll fade if you erase over the top of it, its not water-proof but water-resistant, so it'll run if wet, secondly though they do make them in a small 0.005 millimetre size, yes that's half a millimetre size, I know 'cause I bought one, and it's brilliant for ultra fine detail line work. Bad thing is the smallest size nibs are very difficult to find under 0.02mm size in a retail store. You'll need to go to a speciality art-supply store or order online if you can find them.
I actually prefer to outline in pencil mostly, its easy to adjust and erase, and provided the image is clean you can scan it in fairly easily with a good B/W scanner.
Photoshop I've found is next to useless as a rock when outlining pencil images, yes you can mess around with filters, layers, and adjustments but you won't get a nice clean outline even on a darkened pencil sketch. I know. I've tried a bazillion times. It's a pain in the neck. Better for basic digital colouring if you can get a professional edition copy, yes I know they cost a bundle, but the flexibility if you can afford it is worth it, otherwise there are freeware digital colouring tools out there too like Pixia, SAI, and a bunch I'm not familiar with. Google 'em.
I only really like inking to give a sharp outline to pencil sketches, otherwise, I don't really use it.