Don't wash underwear in hot water. It's totally unnecessary. There are detergents that will work fine in warm or cold water to get underwear clean.
Don't run underwear in a drier on HIGH. That seriously shortens their lifespan, shrinks the heck out of them and blasts the cotton fibers to leave the material thin (and your lint screen rather thick).
For my good quality cotton t-shirts and underwear, I run them in the drier on medium, and also take them out a little early if they're mostly dry. Better to let the slight dampness dry naturally. Another trick is to run the spin cycle one more time, letting centrifugal force help wring out a little more moisture. Also, with any expensive t-shirts or underwear that you've bought (once in a while it's nice to treat yourself to top quality materials), run them in the drier for about 15 minutes then take them out to hang dry.
Using these methods, I have underwear that has been able to last nearly 10 years before showing holes. I have a couple of t-shirts that have survived even longer.
As for brands, I prefer Calvin Klein (they use very good quality cotton) and 2(x)ist. I usually buy 3-packs, but sometimes select solo pieces when on sale. Also, there are some cotton/lycra blends now that make for a great fit and excellent comfort, without binding. Sometimes you can find great deals at TJMaxx.