For those who want to print labels and adhere them... this device (comes in different sizes) may be just the ticket. It's built for "scrapbookers" .. and will take items up to the thickness of a US nickel. What you do is print what your label is to look like, and then pull it through this device... it gets sandwiched between two layers of material. You burnish down around the edges of your label, and pull apart... excess adhesive is pulled away with the top layer and you end up with a label that is now adhesive only on the label backside itself.
http://www.amazon.com/Xyron-Create---Sticker-Machine-Assorted/dp/B0001DU6RS/ref=sr_1_1?ie=UTF8&qid=1421012284&sr=8-1&keywords=Xyron Using this you could use any kind of opaque label material and quickly adhere it to your project.
Another solution (I think mentioned above) is either ink jet or laser waterslide decal paper. You print on it, cut it to size and then use a fixative on it... and apply it like any other decal. Instructions are to print, fix, apply... but I found that if you fix the whole sheet (especially on the ink-jet ones), the water tends to let the excess ink bleed a bit, doing the fixative after trimming the decal closely to size solves that problem, or at least drastically reduces it. One thing to note... light colors need two decals (or more) overlaying to get an opaque lettering result. Once applied, an overcoat of some form of lacquer will help "harden" the result.
If you're going to use waterslide decals, the decal backing can cause a light reflective haze where there is no printing. The typical modeler's approach is a good coat of glosscoat to the base, let dry, use a wetting solution (Microsol, I think it is, have a two step product) to clean the surface and help the decal adhere... then soak the decal in distilled water, apply to the surface... as it dries, microsol setting solution will soften the decal and you can prick any bumps with a fine needle to let the air out... when all is dry, another coat of gloss, followed by dullcoat to completely remove the visible film problem. One advantage to this is that decals can go over textured or curved surfaces.