For those actually doing prints from their photography, whether it be personal or for a client, I would highly recommend picking up a monitor calibration system. In the end it helps save a lot of headaches and insures that what you see on the monitor is what you get when you make prints.
Personally I recently went with the ColorVision Spyder 3 Pro system. I've heard many good things about it and its worked flawlessly for me. There are cheaper options available as well as even more accurate and encompassing products. Regardless find something that fits your budget and it will be a great asset in the long run.
Following that, I've also recently invested in the X-rite ColorChecker Passport after getting a chance to borrow a friend's version. For those serious about correct colors something like this makes a huge help in getting not only correct colors in general but much more accurate skin tones (something that was really big for me). It's quick, it's easy and it's incredibly portable. If you know someone using this system I suggest asking to borrow it for a day or two and see for yourself. If not, you really can't go wrong with picking it up if you're even remotely interested in getting the correct colors and tones in images. The changes may sometimes be subtle but they make a huge impact.
As for the image above, the effect is very subtle but you can see the difference on the models skin tones. The tones are much more natural. In this particular case the original shot, when imported into lightroom and applied with the adobe standard color profile you would normally use leads to much more yellowish tones. Upon applying a profile created by the color checker you end up with much nicer results.