I recently made a big investment in a nice pair of running shoes that, although were a good length and width, were a bit snug over the top. I've been through just about every drugstore insole there is; and as ok as some are, they never lasted, the support was always way to soft, and there was always that feeling of walking on gel (which i don't find as entertaining as some others may).
These are Superfeet Carbons are super low profile; pretty much the lowest. My shoes were a size 10.5 and the size E insoles I got go to size 11 but were still identical in size to the insoles the shoes came with. This meant luckily I had no trimming; but others may want to up the size to keep yourself covered if the sizes are close.
The arch and heel support are very firm; there's still padding, but the form is unyielding. The carbon has Superfeet's lowest arch support. I have flat-ish feet and the arch still felt a bit high. I would say this is for low to even medium arch. I've already gotten used to it, and it feels great now. It's bought me a little more room, and since the material is so strong, I can run in them and not be afraid of the support breaking down like the others. Note the arch height, profile, and size you need and these will serve you well. They're pricey, but will last longer and feel better than the drugstore alternatives that are almost as much anyway.