I've been to a dozen nails salons in the DC area, and I always keep coming back to Modern Nails! They always do a great job, and the results seem to last much longer than other salons!
I always go to Monique, and get a manicure and pedicure. She does a great job, doesn't rush, and it looks great for weeks!
They also do pretty good for acrylic nails, but I gave them up years ago due to the constant expense of fill-ins. Overall, they are very good, though. Henry is good for acrylics. They do great french manicures!
They are also more sanitary than many other salons and I've never had any kind of infection from them here.